Arithmetic Ninja for Ages 9-10 9781801990677, 9781801990660, 1801990670
104 87
English Pages [138]
Cover
Title
Copyright
Contents
Introduction
Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 9
Week 10
Week 11
Week 12
Week 13
Week 14
Week 15
Week 16
Week 17
Week 18
Week 19
Week 20
Week 21
Week 22
Week 23
Week 24
Week 25
Week 26
Week 27
Week 28
Week 29
Week 30
Week 31
Week 32
Week 33
Week 34
Week 35
Week 36
Week 37
Week 38
Week 39
Answers
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ANDREW JENNINGS WITH SARAH FARRELL
ARITHMETIC
NINJA
FOR AGES 9 –10
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BLOOMSBURY EDUCATION Bloomsbury Publishing Plc 50 Bedford Square, London, WC1B 3DP, UK 29 Earlsfort Terrace, Dublin 2, Ireland BLOOMSBURY, BLOOMSBURY EDUCATION and the Diana logo are trademarks of Bloomsbury Publishing Plc First published in Great Britain, 2022 This edition published in Great Britain, 2022 Text copyright © Andrew Jennings, 2022 Ninja illustrations copyright © Andrew Jennings, 2022 Andrew Jennings and Sarah Farrell have asserted their rights under the Copyright, Designs and Patents Act, 1988, to be identified as Authors of this work Bloomsbury Publishing Plc does not have any control over, or responsibility for, any third-party websites referred to or in this book. All internet addresses given in this book were correct at the time of going to press. The author and publisher regret any inconvenience caused if addresses have changed or sites have ceased to exist, but can accept no responsibility for any such changes All rights reserved. This book may be photocopied, for use in the educational establishment for which it was purchased, but may not be reproduced in any other form or by any other means – graphic, electronic, or mechanical, including photocopying, recording, taping or information storage or retrieval systems – without prior permission in writing of the publishers A catalogue record for this book is available from the British Library ISBN: PB: 978-1-8019-9067-7; ePDF: 978-1-8019-9066-0
Text design by Marcus Duck Design
To find out more about our authors and books visit www.bloomsbury.com and sign up for our newsletters
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CONTENTS INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . 5 WEEK 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 WEEK 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 WEEK 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 WEEK 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 WEEK 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 WEEK 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 WEEK 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 WEEK 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 WEEK 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 WEEK 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 WEEK 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 WEEK 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 WEEK 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 WEEK 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 WEEK 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 WEEK 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 WEEK 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 WEEK 18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 WEEK 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 WEEK 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 WEEK 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 WEEK 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 WEEK 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 WEEK 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 WEEK 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 WEEK 26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 WEEK 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 WEEK 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 WEEK 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 WEEK 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 WEEK 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 WEEK 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 WEEK 33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 WEEK 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 WEEK 35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 WEEK 36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 WEEK 37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 WEEK 38. . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 WEEK 39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 ANSWERS. . . . . . . . . . . . . . . . . . . . . . . . . . . 124 3
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OTHER NINJA RESOURCES FOR TEACHERS FOR TEACHERS
TIMES TABLE NINJA BY SARAH FARRELL AND ANDREW JENNINGS A treasure trove of photocopiable multiplication worksheets that give Key Stage 2 pupils all the tools they need to gain fluency in multiplication and division up to their 12 times tables. Each chapter begins with exercises for practising rapid recall, followed by visually engaging activities for applying knowledge to other areas of maths including shape, perimeter, scale factors, fractions and more.
COMPREHENSION NINJA FICTION & POETRY A set of six books for ages 5–11 that provide strategies and carefully curated resources to teach the key comprehension skills of skimming, scanning and retrieving information effectively. Each book curates 24 high-quality fiction or poetry texts by authors such as Roald Dahl, Katherine Rundell and Chitra Soundar, alongside photocopiable activities with strong links to the National Curriculum.
VOCABULARY NINJA
COMPREHENSION NINJA NON-FICTION
A practical guide featuring strategies and photocopiable activities to help transform pupils into vocabulary ninjas. With easyto-follow theory and teaching approaches, as well as key curriculum topic vocabulary, etymology and phrases, this book will help bring the primary curriculum to life.
A set of six books for ages 5–11 that provide strategies and carefully curated resources to teach the key comprehension skills of skimming, scanning and retrieving information effectively. Each book presents 24 high-quality non-fiction texts and photocopiable activities with strong links to the National Curriculum.
FOR CHILDREN WRITE LIKE A NINJA
BE A MATHS NINJA
A pocket-sized book packed full of all the grammar, vocabulary and sentence structures that children need in order to improve and develop their writing skills. Fully aligned to the Key Stage 2 National Curriculum, this book is designed to be used independently by pupils both in the classroom and at home.
Be a Maths Ninja is jam-packed with key concepts, mathematical vocabulary and practice advice to support every child’s growing independence in maths. It covers all the key areas of the National Curriculum for Key Stage 2 and is perfect for children needing all the important maths facts at their fingertips.
Head to www.vocabularyninja.co.uk and follow @VocabularyNinja on Twitter for more teaching and learning resources to support the teaching of vocabulary, reading, writing and the wider primary curriculum.
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INTRODUCTION Arithmetic is the study of a core part of mathematics that involves the varied properties of numbers and how they can be manipulated using the four operations: addition, subtraction, multiplication and division. A pupil’s ability to confidently calculate using the four operations is essential as it underpins their ability to access the reasoning and mastery objectives set out by the primary National Curriculum.
HOW DOES ARITHMETIC NINJA SUPPORT TEACHERS AND SCHOOLS? Arithmetic Ninja has been created to support the daily planning, preparation, teaching and assessment of arithmetic throughout each year group and across the whole school from Year 1 to Year 6. Each book contains almost 6,000 arithmeticstyle questions and word problems that have been tailored to meet the needs of the primary National Curriculum, meaning that high-quality, whole-school arithmetic teaching and learning can be consistently and effectively embedded within each classroom without any of the timeconsuming preparation. It’s teaching simplified, learning amplified. Arithmetic Ninja is another outstanding whole-school resource that embodies the Vocabulary Ninja principles of simplicity, consistency and marginal gains!
HOW TO USE THIS BOOK Arithmetic Ninja is much more than just a series of age-related arithmetic questions. Each day provides three differentiated sets of ten questions. Grasshopper, Shinobi and Grand Master each have a specific focus and purpose to support all pupils in the modern primary classroom. GRASSHOPPER – CATCH-UP AND KEEP UP Grasshopper questions have been designed to support pupils who are not working at the expected standard of their year group and require daily opportunities for repeated practice within a standard mathematical representation of part + part = whole (10 + 4 = 14). Grasshopper questions provide opportunities to build confidence in
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 5
content from three half-terms prior to the age-related expectation. So, questions in the Spring 2 term will include content from Autumn 2, Spring 1 and Spring 2, allowing pupils to not only catch-up, but keep up too! SHINOBI – BUILD LINKS AND MAKE CONNECTIONS Shinobi questions have been created beyond the standard age-related expectation for arithmetic questions. The focus at the Shinobi level is to provide an age-appropriate arithmetic resource – one that provides regular opportunities for pupils to build links and make connections between related mathematical facts. Within the daily series of ten questions, questions have been carefully crafted to allow pupils to make cognitive links between related facts. For example, 9 x 8 = 72 and within the Shinobi series, subsequent questions may focus on 0.8 x 9, 7.2 ÷ 9 or even 0.9 x 0.8. Where possible, the Shinobi strand provides teachers with the mathematical opportunities to dive deeper into a pupil’s understanding with effective questioning to support the link-building process and to make these crucial connections. GRAND MASTER – VARIED FLUENCY, REPRESENTATION AND MASTERY Grand Master questions provide pupils with a greater level of challenge, with questions bridging into mathematical content up to three half-terms beyond the age-related expectation. So, questions in the Autumn 2 term could also contain content from Spring 1 and Spring 2. Grand Master questions go even further still by presenting questions with varied representations such as whole = part + part (200 = 160 + 40) or questions with unknown parts (200 = __ + 40). Grand Master questions allow teachers to provide a greater level of challenge for pupils who are ready for it and are designed to provide opportunities for pupils to develop a mastery level of mathematical understanding. Each Arithmetic Ninja book is an extremely versatile resource for teachers, schools and tutors and could be used to begin daily maths lessons, as part of high-quality intervention, within private tuition or even as part of regular homework provision.
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Autumn term 1: Weeks 1–6 • Number bonds to 10 (alternate representations, e.g. 10 = __ + 4) • Subtract one- and two-digit numbers within 20 (15 – 3 / 15 – 4 / 15 – 5) • Include language of 1 less • Double • Count in 2s (lots of)
Autumn term 2: Weeks 7–12 • Number bonds to 20 (19 + 1 / 1 + 19) • Add and subtract one- and twodigit numbers within 20 (answer box at beginning OR missing number question, e.g. __ – 7 = 9 OR __ = 16 – 9) • Count in 5s (lots of) • 1 more to 50 • 5 + 5 • Half
Spring term 1: Weeks 13–18
• Add and subtract two-digit • Add and subtract two two-digit numbers and tens (34 + 10 / 34 + 20 numbers (56 – 22 / 56 – 23 / / 34 + 30) 56 – 24) • Derive related facts to 100 • Add three one-digit numbers (3 + 4 = 30 / 30 + 40 = 70 / (1 + 5 + 7 / 1 + 4 + 8) 70 = 30 + 40) • 5 times table • Thirds
• Number bonds to 20 (alternate representations, e.g. 20 = __ + 1) • Add and subtract one- and twodigit numbers within 20 (answer box at beginning OR missing number question, e.g. __ – 7 = 9 OR __ = 16 – 9) • Count in 5s (lots of) • 1 less to 50 • 5 + 5 • Half
Spring term 2: Weeks 19–25
• Add and subtract one- and twodigit numbers within 20 (alternate representations including answer box at the beginning AND missing number, e.g. 7 = __ – 9) • Count in 10s (lots of) • 10 + 10 • Quarter • 1 more to 100
Summer term 1: Weeks 26–32
• Three-digit numbers subtract hundreds (456 – 200 / – 300 / – 400) • Derive related facts to 1,000 • Divide one-digit numbers by ten (40 / 10 then 4 / 10) • Non-unit fraction of number (e.g.) relating to times tables
• Add and subtract two two-digit numbers (56 + __ = 79 / 79 = __ + 56) • 5 and 10 times tables
• Mixed adding and subtracting within 20 (alternate representations) and within 30 • Mixed counting in 2s, 5s and 10s • Quarter • 1 less to 100 • Mixed 1 more and 1 less in different representations
Summer term 2: Weeks 33–39
Content map for Arithmetic Ninja Year 1 (for ages 5-6)
• Number bonds to 10, e.g. 9 + 1 / 1+ 9 • Add one- and two-digit numbers within 20 (13 + 1 / 13 + 2 / 13 + 3) • Include language of 1 more • Double • Count in 2s (lots of)
• Addition and subtraction within 20 • Partition two-digit numbers in different ways (20 + 3 / 10 + 13) • Double and half • Quarter
• Three-digit numbers add hundreds (456 + 200 / + 300 / + 400) • Add and subtract three-digit numbers (246 – __ = 132 / 456 = __ + 321) • Derive related facts to 1,000 • Two-digit times one-digit numbers (45 x 3 / 45 x 4)
• Add and subtract decimals (hundredths) • Derive related facts to 10,000 (including fractions of numbers) • Three-digit numbers divided by one-digit numbers
• 10 / 100 / 1000 more / less • Partition numbers in different ways • Add and subtract decimals (complements of 1, e.g. 100 – 76 = __ / 1 – 0.76 =__) • All times tables, including deriving related facts
• 10 / 100 more / less • Mixed times tables (2, 5, 10, 3, 4, 8, including double, half, quarter, etc.) • Multiply three numbers • Add and subtract fractions (same denominators)
• 10 / 100 / 1,000 more / less • Partition four-digit numbers in different ways (3,005 + 340 / 3,300 + 45) • Derive related facts to 10,000 (e.g. 60 x 2) • Unit fractions of numbers
Year 2 (for ages 6-7)
• Add and subtract two-digit and one-digit numbers (34 + 3 / 34 + 5 / 34 + 6) • Using the inverse (1 + 2 = 3 / 3 – 2 = 1) • 2 times table • Half / two quarters
• Three-digit numbers subtract tens (456 – 20 / – 30 / – 40) • Add and subtract three-digit numbers (246 – 123 / 123 + 246) • Distribute (4 x 12 x 5 / 4 x 5 x 12 / 20 x 12 = 240) • Mixed times tables • Unit fractions of numbers linking to those times tables
• Add and subtract decimals (tenths) • Derive related facts to 10,000 (e.g. 600 x 2) • Two-digit numbers divided by one-digit numbers • Add and subtract fractions (same denominators; answers bigger than 1)
• Add and subtract decimals (up to hundredths / different number of places) • Find 100%, 10%, 1% • Find 50%, 20%, 25% • Cube / cube root • Find whole from unit fraction • Multiply mixed numbers by whole numbers
• Powers of 10 more / less • Square / square root • Short multiplication • Derive related facts to 10,000 (including fractions) • Add and subtract fractions with the same denominator (answers bigger than 1)
• Add and subtract more than fourdigit numbers (84,564 + 12,323 = __ / __ = 84,564 + 12,323) • Multiply and divide by 10, 100 and 1000 • Derive related facts to 100,000 (including fractions) • Add and subtract fractions where the denominators are multiples of same number (answers bigger than 1)
• Number bonds to 10 (alternate representations) • Number bonds to 20 (alternate representations) • Addition and subtraction within 10 • Count in 2s • Double
• Three-digit numbers add tens (456 + 20 / + 30 / + 40) • Derive related facts (30 + 40 / 300 + 400 / 50 + 20) • 8 times table • Add and subtract fractions with the same denominator ( + )
• Add and subtract four-digit numbers (4564 + 2323 = __ / 5737 = __ – 1234) • Derive related facts to 10,000 (including fractions of numbers) • Three-digit times one-digit numbers • Divide a one- or two-digit number by 10 and 100
• Add and subtract decimals (up to hundredths / mix of whole and decimal) • Short division • Multiply simple fractions by whole numbers
• Decimal division • Divide mixed number by whole number
• Short division • Long division • Divide fractions by whole numbers • Mixed fractions and percentages of numbers • Fractions to decimals
Year 3 (for ages 7-8)
• Three-digit numbers subtract ones (456 – 2 / – 3 / – 4) • Partition three-digit numbers in different ways (100 + 40 + 6 / 130 + 16) • 3 and 4 times tables (including quarters)
• Add and subtract four-digit numbers (4564 + 2323 = __ / __ = 4564 + 2323) • Derive related facts to 10,000 (e.g. 600 x 2) • Three-digit times one-digit numbers • Non-unit fractions of numbers
• Add and subtract more than fourdigit numbers (84,564 + 12,323 = __ / 45,737 = __ – 31,234) • Long multiplication • Short division (no remainders) • Non-unit fractions of whole numbers • Add and subtract mixed numbers
• Decimal long multiplication • Multiply mixed pairs of fractions
• Square and cube numbers • BODMAS • Long multiplication • Multiply pairs of fractions • Find whole from fraction • Percentage of number
• Three-digit numbers add ones (456 + 2 / + 3 / + 4) • Partition two-digit numbers in different ways (80 + 2 / 70 + 12) • Mixed 2, 5 and 10 times tables (including halves and doubles)
Year 4 (for ages 8-9)
Year 5 (for ages 9-10)
Year 6 (for ages 10-11)
• Mixed decimal addition and subtraction • Derive related facts to 1,000,000 • Add and subtract fractions with different denominators • Fraction of number
• Mixed whole number addition and subtraction • Derive related facts to 100,000 • Multiply and divide by 10, 100 and 1,000 • Add and subtract fractions with denominators that are multiples of the same number
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Arithmetic Ninja 9–10 © Andrew Jennings, 2022
6
GRASSHOPPER LEVEL
WEEK 1 Monday
Tuesday
1.
3,204
+
1,000
=
1.
4,904
+
100
=
2.
1,384
+
838
=
2.
2,731
+
916
=
3.
2.4
+
1.3
=
3.
3.2
+
1.7
=
4.
1,047
–
100
=
4.
1,069
–
100
=
5.
5,283
–
843
=
5.
4,104
–
596
=
6.
2.4
–
1.2
=
6.
3.9
–
2.3
=
7.
8
x
5
=
7.
6
x
7
=
8.
9
x
7
=
8.
9
x
5
=
9.
36
÷
4
=
9.
16
÷
4
=
10.
24
÷
3
=
10.
28
÷
7
=
Wednesday
Thursday
1.
1,012
+
100
=
1.
945
+
100
=
2.
3,705
+
904
=
2.
3,473
+
1,273
=
3.
4.5
+
2.6
=
3.
8.4
+
1.8
=
4.
1,839
–
100
=
4.
2,384
–
100
=
5.
3,045
–
672
=
5.
3,470
–
1,263
=
6.
4.1
–
1.8
=
6.
5.2
–
0.8
=
7.
8
x
3
=
7.
9
x
5
=
8.
12
x
3
=
8.
8
x
8
=
9.
44
÷
11
=
9.
36
÷
6
=
10.
35
÷
7
=
10.
32
÷
4
=
Friday 1.
1,915
+
100
=
2.
4,329
+
2,366
=
3.
7.3
+
2.4
=
4.
3,471
–
100
=
5.
5,488
–
1,263
=
6.
6.2
–
1.6
=
7.
8
x
5
=
8.
6
x
9
=
9.
25
÷
5
=
10.
49
÷
7
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 7
Ninja challenge
Cho has 3,500 marbles. Tom says he has 870 marbles less than Cho. How many marbles does Tom have?
7
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v
SHINOBI LEVEL
WEEK 1 Monday 1.
7,423
2.
Tuesday
+
10
=
=
7,423
+
1,000
is equal to
1. 100
5,697
2.
+
10
=
=
5,697
+
1,000
=
3.
5,697
+
4.
0.97
+
+
5.
1
=
0.22
+
4,006
+
6.
3,006
+
670
=
=
4,207
+
7.
5,685
=
5,600
+
4
x
3
=
8.
4
x
6
=
9.
3
x
4
=
9.
6
x
4
=
10.
30
x
4
=
10.
6
x
40
=
3.
7,423
add
4.
0.45
+
5.
1
=
0.23
6.
4,506
=
7.
4,217
8.
=
1
Wednesday 1.
2,485
2.
10
=
=
2,485
+
1,000
=
2,485
+
4.
0.67
+
5.
1
=
0.87
6.
3,060
+
7.
7,695
8.
1. 100
6,797
2.
+
10
=
=
6,797
+
1,000
=
3.
6,897
+
4.
0.51
+
+
5.
1
=
0.99
+
308
=
6.
9,040
+
804
=
=
7,005
+
7.
5,694
=
5,600
+
2
x
9
=
8.
11
x
6
=
9.
9
x
2
=
9.
6
x
11
=
10.
9
x
20
=
10.
60
x
11
=
=
1
2,482
2.
+
10
=
=
2,482
+
1,000
is equal to
3.
2,482
add
4.
0.01
+
5.
1
=
0.12
+
6.
9,900
+
45
=
7.
3,685
=
3,005
+
8.
5
x
6
=
9.
6
x
5
=
10.
60
x
5
=
=
8
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 8
=
100 1
Ninja challenge
Friday 1.
1
Thursday
+
3.
=
100
100
Sam says that 3 groups of 40 is equal to 120. Is Sam correct? Explain why.
1
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
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GRAND MASTER LEVEL
WEEK 1 Monday
Tuesday
1.
=
22.5
plus
14.7
1.
=
31.3
plus
20.9
2.
equals
14.5
–
6.7
2.
equals
21.3
–
9.5
3.
=
40
x
9
3.
=
50
x
7
4.
=
81
÷
9
4.
=
72
÷
8
5.
equals
263
times
5
5.
equals
187
times
6
6.
÷
10
=
5.7
6.
÷
10
=
6.4
7.
=
43
÷
10
7.
=
87
÷
10
8.
=
43,483
+
37,408
8.
=
51,038
+
19,445
9.
=
50,394 subtract 17,490
9.
=
60,394 subtract 21,809
10.
8 9
3 9
=
10.
add
6 9
Wednesday
=
1 9
add
Thursday
1.
=
45.4
plus
22.7
1.
=
56.2
plus
31.9
2.
equals
31.6
–
11.9
2.
equals
30.5
–
15.9
3.
=
70
x
6
3.
=
90
x
6
4.
=
48
÷
8
4.
=
32
÷
8
5.
equals
206
times
8
5.
equals
274
times
6
6.
÷
10
=
5.6
6.
÷
10
=
9.4
7.
=
92
÷
10
7.
=
82
÷
10
8.
=
65,084
+
32,388
8.
=
78,384
+
28,808
=
75,301 subtract 43,212
9.
=
81,289 subtract 30,047
9. 10.
7 8
6 8
=
10.
add
Friday 1.
=
62.7
plus
42.8
2.
equals
45.1
–
16.8
3.
=
70
x
9
4.
=
96
÷
8
5.
equals
327
times
7
6.
÷
10
=
8.1
7.
=
93
÷
10
8.
=
75,083
+
34,906
9.
=
83,008 subtract 45,381
10.
10 13
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 9
7 13
9 12
=
6 12
add
Ninja challenge
Cho says that 39,463 is 9,362 more than 29,236. Is Cho correct? Explain why.
add 9
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 2 Monday
Tuesday
1.
10,682
+
1,377
=
1.
11,103
+
2,374
=
2.
4,391
+
3,489
=
2.
5,481
+
4,883
=
3.
0.6
+
0.9
=
3.
0.9
+
1.4
=
4.
13,638
–
4,045
=
4.
14,034
–
3,412
=
5.
5,183
–
1,958
=
5.
6,518
–
1,405
=
6.
6.2
–
0.9
=
6.
7.2
–
1.4
=
7.
8
x
3
=
7.
7
x
4
=
8.
60
x
4
=
8.
50
x
6
=
9.
30
÷
5
=
9.
54
÷
6
=
10.
420
÷
7
=
10.
220
÷
2
=
Wednesday
Thursday
1.
10,812
+
2,710
=
1.
11,523
+
3,469
=
2.
6,031
+
2,903
=
2.
7,293
+
1,374
=
3.
4.2
+
2.9
=
3.
5.4
+
1.8
=
4.
10,385
–
5,146
=
4.
13,156
–
6,532
=
5.
7,021
–
2,911
=
5.
5,310
–
2,202
=
6.
8.3
–
0.8
=
6.
4.1
–
1.2
=
7.
4
x
3
=
7.
5
x
8
=
8.
60
x
7
=
8.
40
x
7
=
9.
27
÷
9
=
9.
64
÷
8
=
10.
450
÷
5
=
10.
480
÷
6
=
Friday 1.
13,294
+
2,416
=
2.
8,374
+
2,231
=
3.
6.3
+
2.9
=
4.
12,798
–
3,217
=
5.
6,032
–
1,391
=
6.
5.6
–
2.1
=
7.
7
x
8
=
8.
70
x
3
=
9.
24
÷
6
=
10.
180
÷
3
=
10
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 10
Ninja challenge
Sam has 60 groups of 4 counters. He tells Iko that he has 220 counters. Is Sam correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 2 Monday 1.
34,493
2.
Tuesday
+
10
=
=
34,493
+
1,000
=
3.
34,493
+
4.
0.56
+
5.
1
=
0.05
6.
30,504
+
7.
89,593
8.
1. 100
48,947
2.
+
10
=
=
48,947
+
1,000
=
3.
48,947
+
4.
0.04
+
+
5.
1
=
0.68
+
8,060
=
6.
30,006
+
4,960
=
=
89,003
+
7.
89,593
=
80,093
+
8
x
9
=
8.
5
x
7
=
9.
9
x
8
=
9.
7
x
5
=
10.
90
x
8
=
10.
70
x
5
=
=
1
Wednesday 1.
67,329
2.
10
=
=
67,329
+
1,000
=
67,329
+
4.
0.82
+
5.
1
=
0.91
6.
80,500
+
7.
13,434
8.
1. 100
56,482
2.
+
10
=
=
56,482
+
1,000
=
3.
56,482
+
4.
0.36
+
+
5.
1
=
0.69
+
2,056
=
6.
78,004
+
520
=
=
10,030
+
7.
94,596
=
90,090
+
2
x
8
=
8.
2
x
4
=
9.
8
x
2
=
9.
4
x
2
=
10.
80
x
2
=
10.
40
x
2
=
=
1
42,596
2.
+
10
=
=
42,596
+
1,000
=
3.
42,596
+
4.
0.07
+
5.
1
=
0.11
+
6.
90,030
+
3,406
=
7.
67,294
=
60,004
+
8.
5
x
9
=
9.
9
x
5
=
10.
90
x
5
=
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 11
=
100 1
Ninja challenge
Friday 1.
1
Thursday
+
3.
=
100
100
Cho says that half of 2,000 is equal to double 500. Is Cho correct? Explain why.
1
11
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 2 Monday
Tuesday
1.
=
83.4
minus
37.2
1.
=
83.1
minus
77.5
2.
equals
77.2
–
52.4
2.
equals
43.6
–
12.9
3.
=
60
x
60
3.
=
50
x
90
4.
=
480
÷
8
4.
=
320
÷
8
5.
equals
421
times
5
5.
equals
352
times
3
6.
÷
100
=
8.1
6.
÷
100
=
4.3
7.
=
410,000
÷
100
7.
=
350,000
÷
100
8.
=
36,830
add
29,304
8.
=
45,803
add
35,384
9.
=
95,304 subtract 65,495
9.
=
95,304 subtract 56,410
10.
4 13
7 13
=
10.
take away
1 13
Wednesday
10 13
=
take away
Thursday
1.
=
71.4
minus
56.3
1.
=
66.8
minus
47.5
2.
equals
56.4
–
23.9
2.
equals
34.5
–
22.5
3.
=
70
x
30
3.
=
80
x
80
4.
=
560
÷
8
4.
=
720
÷
8
5.
equals
615
times
5
5.
equals
415
times
5
6.
÷
100
=
6.2
6.
÷
100
=
7.1
7.
=
290,000
÷
100
7.
=
830,000
÷
100
8.
=
30,485
add
27,778
8.
=
50,405
add
41,205
=
104,384 subtract 37,405
9.
=
101,274 subtract 43,475
9. 10.
4 14
13 14
=
10.
take away
Friday 1.
=
78.2
minus
32.3
2.
equals
68.3
–
56.1
3.
=
90
x
80
4.
=
960
÷
8
5.
equals
723
times
6
6.
÷
100
=
8.5
7.
=
110,000
÷
100
8.
=
90,384
add
51,294
9.
=
114,304 subtract 93,492
10.
3 15
=
14 15
12
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 12
7 14
=
11 14
take away
Ninja challenge
Iko subtracts 10,000 from 323,392. What is her answer?
take away
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 3 Monday
Tuesday
1.
12,313
+
3,461
=
1.
14,235
+
1,388
=
2.
8.3
+
4.9
=
2.
7.1
+
3.2
=
3.
9,284
–
4,133
=
3.
7,385
–
3,212
=
4.
7.1
–
3.5
=
4.
5.4
–
1.8
=
5.
6
x
7
=
5.
4
x
9
=
6.
20
x
9
=
6.
70
x
9
=
7.
36
÷
4
=
7.
24
÷
4
=
8.
320
÷
8
=
8.
240
÷
2
=
9.
3 6 3 7
+
2 6
=
9.
+
2 6
=
of
21
=
10.
2 6 3 9
of
36
=
10.
Wednesday
Thursday
1.
13,104
+
2,362
=
1.
11,153
+
3,416
=
2.
8.4
+
6.5
=
2.
9.3
+
4.5
=
3.
8,261
–
5,001
=
3.
9,374
–
3,231
=
4.
6.2
–
3.4
=
4.
8.4
–
1.9
=
5.
6
x
9
=
5.
7
x
4
=
6.
40
x
9
=
6.
60
x
12
=
7.
18
÷
2
=
7.
16
÷
2
=
8.
240
÷
3
=
8.
420
÷
6
=
9.
2 6 3 8
+
3 6
=
9.
+
4 7
=
of
24
=
10.
2 7 5 9
of
36
=
10.
Friday 1.
13,405
+
4,377
=
2.
10.4
+
1.3
=
3.
8,384
–
4,173
=
4.
9.2
–
3.5
=
5.
5
x
5
=
6.
70
x
5
=
7.
27
÷
9
=
8.
720
÷
6
=
9.
1 7 7 9
+
4 7
=
of
27
=
10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 13
Ninja challenge
Tom starts with the number 480. He halves it, then halves it again. What number does Tom finish with?
13
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 3 Monday 1.
67,049
2.
Tuesday
–
10
=
=
67,049
–
1,000
=
3.
67,049
–
4.
0.53
+
5.
1
=
0.89
6.
50,607
+
7.
23,969
8.
1. 100
36,495
2.
–
10
=
=
36,495
–
1,000
=
3.
36,495
–
4.
0.04
+
+
5.
1
=
0.34
+
3,040
=
6.
20,006
+
4,560
=
=
20,900
+
7.
78,695
=
8,690
+
3
x
8
=
8.
4
x
8
=
9.
8
x
3
=
9.
8
x
4
=
10.
80
x
3
=
10.
80
x
4
=
=
1
Wednesday 1.
67,492
2.
10
=
=
67,492
–
1,000
=
67,492
–
4.
0.59
+
5.
1
=
0.23
6.
50,050
+
7.
78,593
8.
1. 100
78,594
2.
–
10
=
=
78,594
–
1,000
=
3.
78,594
–
4.
1
–
+
5.
0.23
=
1
–
6,309
=
6.
90,600
+
5,034
=
=
70,500
+
7.
34,594
+
30,090
=
7
x
8
=
8.
12
x
3
=
9.
8
x
7
=
9.
3
x
12
=
10.
80
x
7
=
10.
30
x
12
=
=
1
30,405
2.
–
10
=
=
30,405
–
1,000
=
3.
30,404
–
4.
1
–
5.
0.03
=
1
–
6.
74,003
+
450
=
7.
29,485
=
20,405
=
8.
11
x
5
=
9.
5
x
11
=
10.
50
x
11
=
=
14
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 14
=
100 0.44
Ninja challenge
Friday 1.
1
Thursday
–
3.
=
100
100
Iko shares 240 equally by 80. What answer will Iko get?
0.13
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 3 Monday 1.
Tuesday
=
34,301
+
1.29
=
2.
2.33
+
3.
0.05
+
=
4.
1
=
5.
1,000
more than
6.
+
=
1
+
0.83
4.
1
=
+
0.77
=
329,485
5.
1,000
more than
=
403,104
1.39
6.
1.36
=
8.
=
2,999
+
9.
100
more than
10.
22
+
=
+
0.43
=
347,402
+
604
=
8.
=
3,909
+
1,909
9.
100
more than
=
103,585
10.
32
+
7. 1,999 938,112
=
Wednesday 55,374
+
3.87
=
2.
6.32
+
3.
0.08
+
=
4.
1
=
+
1,000
more than
15,374
117
=
8.
=
2,009
+
9.
100
more than
10.
32
+
=
+
3.17
=
+
=
1
0.46
4.
1
=
+
0.41
1,000
more than
=
703,481
1.61
1,989 122,474
39,481
8.59
+
3.
0.42
+
=
1
4.
1
=
+
0.98
5.
1,000
more than
=
524,495
1.58
+
0.31
=
+
374
=
8.
=
2,909
+
1,499
9.
100
more than
=
248,119
10.
42
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 15
52
+
0.64
=
205,488
+
349
=
8.
=
3,401
+
1,699
9.
100
more than
=
122,474
10.
32
+
7.
2.
109,384
=
0.14
Friday 46,381
4.12
20,485
3.
=
=
+
1
6.
+
75,374
+
0.89
404,472
= 8.34
5.
=
7.
=
2.
286,384
0.16
6.
1.
=
+
1.
32
Thursday
=
22
=
0.03
375
7.
2.47
21,394
3.
+
6.
+
1
230,384
5.
45,034
+
=
1.
= 5.05
0.56
32
1. 2.
+
7.
11,294
52
=
Ninja challenge
Sam says that 700 groups of 9 is equal to 11 groups of 600. Is Sam correct? Explain why.
= 15
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 4 Monday
Tuesday
1.
2,369
more than
11,272
=
1.
3,021
more than
12,934
=
2.
0.43
plus
0.32
equals
2.
0.53
plus
0.19
equals
3.
1,264
less than
4,179
=
3.
1,904
less than
5,567
=
4.
0.78
minus
0.15
is equal to
4.
0.79
minus
0.14
is equal to
5.
5
groups of
5
=
5.
7
groups of
4
=
6.
600
x
3
=
6.
400
x
7
=
7.
36
divided by
9
=
7.
32
divided by
8
=
8.
300
÷
6
equals
8.
480
÷
6
equals
9.
6 7 7 9
–
4 7
=
9.
–
6 8
=
of
63
=
10.
7 8 7 12
of
48
=
1.
4,364
more than
11,384
=
1.
5,045
more than
12,639
=
2.
0.42
plus
0.37
equals
2.
0.52
plus
0.37
equals
3.
2,174
less than
4,379
=
3.
3,284
less than
9,059
=
4.
0.93
minus
0.45
is equal to
4.
0.91
minus
0.67
is equal to
5.
9
groups of
3
=
5.
8
groups of
9
=
6.
300
x
7
=
6.
600
x
7
=
7.
42
divided by
7
=
7.
55
divided by
5
=
8.
320
÷
4
equals
8.
540
÷
6
equals
9.
7 9 5 9
–
3 9
=
9.
–
7 10
=
of
72
=
10.
9 10 5 10
of
90
=
10.
Wednesday
10.
Thursday
Friday 1.
3,274
more than
12,367
=
2.
0.23
plus
0.43
equals
3.
1,366
less than
7,746
=
4.
0.82
minus
0.54
is equal to
5.
7
groups of
9
=
6.
400
x
5
=
7.
27
divided by
3
=
8.
180
÷
3
equals
9.
5 10 3 10
–
4 10
=
of
60
=
10. 16
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 16
Ninja challenge
Iko says that if she equally shares 280 marbles into 4 groups, that she will have 60 marbles in each group. Is she correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 4 Monday 1.
80,503
2.
Tuesday
–
10
=
=
80,503
–
1,000
=
3.
80,503
–
4.
1
–
5.
0.45
=
1
6.
80,005
+
7.
78,192
8.
1. 100
67,954
2.
–
10
=
=
67,954
–
1,000
=
3.
67,954
–
4.
1
–
–
5.
0.08
=
1
–
6,690
=
6.
90,405
+
8,060
=
=
78,002
+
7.
81,394
=
80,004
+
8
x
9
=
8.
8
x
7
=
9.
80
x
9
=
9.
80
x
7
=
10.
800
x
9
=
10.
800
x
7
=
=
0.14
Wednesday 1.
12,039
2.
10
=
=
12,039
–
1,000
=
12,039
–
4.
1
–
5.
0.32
=
1
6.
20,405
+
7.
67,391
8.
1. 100
596,493
2.
–
10
=
=
596,493
–
1,000
=
3.
596,493
–
4.
1
–
–
5.
0.94
=
1
–
3,090
=
6.
500,505
+
76,090
=
=
60,001
+
7.
697,594
=
607,500
+
7
x
9
=
8.
8
x
12
=
9.
70
x
9
=
9.
80
x
12
=
10.
700
x
9
=
10.
800
x
12
=
=
0.56
875,109
2.
–
10
=
=
875,109
–
1,000
=
3.
875,109
–
4.
1
=
5.
0.61
=
1
–
6.
200,100
+
4,093
=
7.
517,093
=
500,090
+
8.
9
x
3
=
9.
90
x
3
=
10.
900
x
3
=
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 17
=
100 0.55
Ninja challenge
Friday 1.
0.62
Thursday
–
3.
=
100
100
Cho says that 10 less than 1,904 is greater than 1,000 more than 905. Is Cho correct? Explain why.
0.77
17
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 4 Monday 1.
Tuesday
=
46,381
plus
39,481
1.
=
57,495
plus
40,384
2.
18.59
add
3.17
=
2.
17.23
add
5.37
=
3.
1.42
plus
1.2
equals
3.
2.31
plus
3.4
equals
4.
10
=
4.
10
=
5.
10
more than
203,475
=
5.
10
more than
317,263
=
6.
11.53
add
1.23
equals
6.
12.41
add
3.12
equals
7.
109,384
+
101,459
=
7.
110,283
+
94,853
=
8.
=
14,302
+
8.
=
34,291
+
3,210
9.
100
more than
9.
100
more than
=
17,373
10.
22
+
10.
42
+
+
= 52
8.98
1,504 53,140
equals
Wednesday 1.
+
32
8.36
equals
Thursday
=
62,384
plus
47,312
1.
=
43,980
plus
34,921
2.
18.32
add
6.89
=
2.
21.36
add
6.49
=
3.
4.17
plus
2.3
equals
3.
5.31
plus
4.6
equals
4.
10
=
4.
10
=
5.
10
more than
219,284
=
5.
10
more than
435,492
=
6.
14.23
add
7.3
equals
6.
16.41
add
8.3
equals
7.
114,283
+
104,381
=
7.
132,305
+
105,482
=
8.
=
54,202
+
8.
=
63,902
+
1,506
9.
100
more than
9.
100
more than
=
32,283
10.
52
+
10.
62
+
+
= 52
7.86
8,930 15,653
equals
Friday 1.
=
19,394
plus
18,205
2.
25.36
add
7.43
=
3.
8.43
plus
7.5
equals
4.
10
=
5.
10
more than
126,481
=
6.
17.05
add
4.2
equals
7.
176,393
+
110,284
=
8.
=
57,304
+
2,305
9.
100
more than
=
52,145
10.
52
+
+
42
18
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 18
+
32
6.33
equals
Ninja challenge
Tom has 6 groups of 871. Tom says that the total of the 6 groups is equal to 5,226. Is Tom correct? Explain why.
5.88
equals Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 5 Monday 12,367
1,000
more than more than less than less than
5.
4
6.
1.
10
2.
100
3.
10
4.
Tuesday 13,261
1,000
more than more than less than less than
5.
6
=
6.
4
=
shared by
3
equals
+
10 19
of
35
1.
10
14,273 equals
2.
100
7,801
=
3.
10
14,274
is equal to
4.
lots of
7
=
600
times
7
7.
32
divided by
8.
240
9.
5 19 3 7
10.
=
1.
10
=
20,304
is equal to
lots of
8
=
500
times
9
=
7.
16
divided by
4
=
8.
150
shared by
3
equals
=
9.
+
8 19
=
=
10.
7 19 6 7
of
63
=
2.
100
3.
10
4.
1,000
5.
5
6.
Thursday 1.
10
9,084 equals
2.
100
2,395
=
3.
10
10,803
is equal to
4.
1,000
more than more than less than less than
lots of
8
=
5.
7
200
times
9
=
6.
7.
32
divided by
4
=
8.
360
shared by
3
equals
9.
6 19 6 9
+
10 19
of
36
10.
15,041
=
10
2.
100
3.
10
4.
1,000
more than more than less than less than
5.
9
6.
9,112
is equal to
lots of
8
=
300
times
9
=
7.
44
divided by
4
=
8.
540
shared by
9
equals
=
9.
+
10 21
=
=
10.
10 21 6 7
of
35
=
= =
26,371
is equal to
lots of
8
=
600
times
9
=
7.
27
divided by
3
=
8.
720
shared by
8
equals
9.
11 21 6 9
+
5 21
=
of
81
=
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 19
11,932 equals 9,945
8,384 equals
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
= =
10,843
10.
8,003 3,729
Friday 1.
13,203 equals 3,405
Wednesday more than more than less than less than
=
Ninja challenge
Cho doubles 86. She takes the answer and doubles it again. What number does Cho have?
19
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 5 Monday
Tuesday
10
less than
=
+ 1,000
more than
1.
495,594
is
2.
495,694
100
10
more than
=
– 1,000
less than
1.
275,349
is
2.
275,349
3.
275,349
is
4.
0.23
+
–
5.
1
=
=
230,507 +
6.
=
545,500 +
x
3
900
x
9,000
x
3.
495,594
is
4.
0.56
+
5.
0.32
=
1
6.
200,007 +
34,580
7.
500,504 +
8.
90
9. 10.
=
1
0.91
+
300,030 + 79,203
=
300,000 +
7.
700,000 +
=
703,404 +
=
8.
2
x
90
=
3
=
9.
2
x
900
=
3
=
10.
2
x
9,000
=
94
Wednesday 365,495
is
2.
365,495
=
3.
365,495
is
4.
0.07
+
+
5.
1
=
=
860,006 +
6.
207,500 +
=
203,005 +
7.
100,005 +
x
8
=
8.
700
x
8
=
7,000
x
8
=
855,590
is
2.
855,590
=
3.
855,590
is
4.
0.05
+
5.
1
=
0.83
6.
805,800 +
60,066
7.
200,505 +
8.
70
9. 10.
10
+ 1,000
100
more than
=
1
540
10
less than
=
+ 1,000
more than
is
2.
845,594
3.
845,594
is
4.
0.11
+
5.
1
=
6.
700,200 +
7.
100,005 +
8.
= 0.08
+
=
730,009 +
42,030
=
140,030 +
60
x
4
=
9.
600
x
4
=
10.
6,000
x
4
=
20
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 20
20,050
10
more than
– 1,000
100
less than
= 0.45
+
=
290,008 +
3,790
=
103,700 +
20
x
11
=
9.
200
x
11
=
10.
2,000
x
11
=
1 7,590
Ninja challenge
Friday 845,594
1
Thursday less than
1.
1.
1.
=
100
100
Sam counts on 9 lots of 100 from 6,701. What number does Sam count on to?
1 250
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 5 Monday 1.
20,304 minus 13,495
=
2.
9.43
take away
3.
8
subtract
4. 5. 6.
10
less than
11.34 minus
7. 8.
3.4
= 10
Tuesday
–
15,399
8,911
=
9.
100
less than
10.
32
–
=
11.35
take away
8
subtract
0.9
3.
–
3.4
4.
=
126,471
5.
equals
5.94
6.
=
68,096
7.
–
673
8.
51,284
equals
=
2.
equals
= 22
1.
= 10
2.
14.52
take away
3.
9
subtract
4.
=
5.
10
less than
6.
10
14.94 minus
7. 8.
8.4
–
19,206
7,488
=
9.
100
less than
10.
72
–
=
–
=
2.
17.85
take away
3.
8
subtract
4. 5. 6.
= 10
10
less than
16.38 minus
7.
–
4.3
–
5.3
=
132,374
equals 10.41 23,490
=
22,122
=
–
829
9.
100
less than
=
43,181
10.
42
–
1.
=
2.
16.22
take away
4
subtract
10
3.
–
7.3
4.
= less than
=
203,395
5.
equals
7.54
6.
=
37,498
7.
–
917
8.
51,185
equals
51,364 minus 9,261 7.4
equals
6,552
2.9
Friday 1.
less than
equals
= 32
10
=
22
equals
Thursday
37,271 minus 6,471
=
8.5
15.31 minus
Wednesday 1.
19,293 minus 4,833
= equals
4.5
–
1.6
=
194,370
42,384 minus 8,302 9.3 10
16.31 minus –
24,366
= equals
1.9
–
8.5
=
160,937
equals
7.81
=
46,008
4,558
=
–
847
9.
100
less than
=
51,185
10.
92
–
62
equals
Ninja challenge
Tom says that 132,743 is 10,000 less than 133,743. Is Tom correct? Explain why.
equals 11.78 15,302
=
49,009
8.
3,595
=
–
716
9.
100
less than
=
64,681
10.
72
–
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 21
42
equals 21
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 6 Monday
Tuesday
1.
0.67
plus
0.56
=
1.
0.71
plus
0.49
=
2.
1.57
minus
0.61
is equal to
2.
1.32
minus
0.73
is equal to
3.
half
of
60
=
3.
half
of
120
=
4.
3
x
43
=
4.
4
x
52
=
5.
7
lots of
8
equals
5.
3
lots of
8
equals
6.
200
times
10
=
6.
600
times
7
=
7.
64
divided by
8
=
7.
32
divided by
8
=
8.
360
shared by
9
equals
8.
420
shared by
7
equals
9.
4 7 2 9
+
5 7
=
9.
+
3 7
=
of
27
is equal to
10.
5 7 2 3
of
27
is equal to
10.
Wednesday
Thursday
1.
0.86
plus
0.56
=
1.
0.78
plus
0.32
=
2.
1.12
minus
0.67
is equal to
2.
1.31
minus
0.95
is equal to
3.
half
of
260
=
3.
half
of
480
=
4.
6
x
27
=
4.
7
x
35
=
5.
6
lots of
8
equals
5.
8
lots of
8
equals
6.
500
times
7
=
6.
400
times
7
=
7.
42
divided by
6
=
7.
108
divided by
9
=
8.
150
shared by
5
equals
8.
550
shared by
5
equals
9.
5 9 2 7
+
7 9
=
9.
+
8 9
=
of
49
is equal to
10.
6 9 6 7
of
84
is equal to
10.
Friday 1.
0.96
plus
0.82
=
2.
1.56
minus
0.97
is equal to
3.
half
of
620
=
4.
8
x
43
=
5.
8
lots of
2
equals
6.
400
times
9
=
7.
96
divided by
8
=
8.
720
shared by
9
equals
9.
9 10 2 5
+
8 10
=
of
45
is equal to
10. 22
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 22
Ninja challenge
Sam says that 1,250 more than 980 is 2,365. Is Sam correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 6 Monday
Tuesday
10
more than
=
– 1,000
less than
1.
134,969
is
2.
134,969
3.
134,969
is
4.
0.342
+
5.
1
=
6.
300,200 +
7.
902,050 +
8.
=
100 1
3.
729,184
is
4.
0.742
+
5.
1
=
6.
605,070 +
309
=
900,300 +
7.
100,500 +
60
x
7
=
8.
9.
60
x
70
=
10.
60
x
700
=
2.
183,503
=
3.
183,503
is
+
=
640,006 +
30,097
=
130,007 +
30
x
8
=
9.
300
x
8
=
10.
3,000
x
8
=
4.
0.503
+
5.
1
=
6. 7.
100
less than
=
1
1.
924,097
is
2.
924,097
=
3.
924,097
is
4.
0.593
+
5.
1
=
6.
500,200 +
0.361
+
200,400 +
=
201,050 +
43,500 + 900,013
=
3,013 +
7.
705,008 +
406
10
– 1,000
= 0.026
+
=
501,003 +
80,540
=
5,048 +
x
80
=
8.
11
x
60
=
9.
7
x
800
=
9.
11
x
600
=
10.
7,000
x
8
=
10.
11
x
6,000
=
10
more than
=
+ 1,000
less than
2.
283,005
100
3.
283,005
is
4.
0.385
+
5.
1
=
6.
105,800 +
=
20,800 + 105,052
7.
60,254 + 905,000
=
960,050 +
= 0.052
12
x
80
=
9.
12
x
800
=
10.
12
x
8,000
=
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 23
1 30,200
Sam says that 7 groups of 80 is equal to 640. Is Sam correct? Explain why.
1
+
8.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
100
Ninja challenge
Friday is
5,870
more than
7
283,005
1
less than
8.
1.
100
Thursday more than
+ 1,000
= 0.021
Wednesday 10
1,000
729,184
300,055 +
is
+ more than
2.
=
183,503
=
is
+
1.
less than
729,184
0.009
30,200
10
1.
23
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 6 Monday 1.
Tuesday
=
30,412
–
9.6
=
2.
23.77
–
3.
9
–
7,137
1.
=
32,089
–
9.9
=
2.
26.92
–
11
–
=
4.4
3.
8,707
=
5.2
4.
=
100
–
91.6
4.
=
100
–
75.9
5.
–
1,000
=
152,635
5.
–
1,000
=
171,887
=
12.28
6.
18.56
–
=
11.76
7.
60,000
–
6,094
=
6.
17.98
–
7.
50,000
–
8.
3,176
=
9. 10.
82
23,768
= –
824
8.
76,966
9.
–
10
=
–
52
=
10.
112
Wednesday 1.
41,089
–
6.8
=
27.65
–
3.
12
–
= –
906 65,079
–
10
=
–
22
=
Thursday
=
2.
17,665
6,113
1.
=
52,087
–
7.7
=
2.
25.65
–
13
–
=
5.8
3.
7,101
=
5.5
4.
=
100
–
36.7
4.
=
100
–
42.5
5.
–
1,000
=
144,087
5.
–
1,000
=
150,888
=
16.28
6.
19.56
–
=
14.46
7.
50,000
–
8,295
=
6.
17.08
–
7.
40,000
–
8.
7,121
=
9. 10.
102
19,805
= –
879
8.
56,101
9.
–
10
=
–
82
=
10.
Friday 1.
=
61,555
–
8.9
=
2.
13.67
–
3.
15
–
8,511
=
7.2
4.
=
100
–
34.3
5.
–
1,000
=
164,856
=
12.26
6.
20.76
–
7.
70,000
–
8.
8,493
=
9. 10.
62
32,565
–
507 17,525
10
=
–
32
=
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 24
= –
705 43,799
–
10
=
–
82
=
Ninja challenge
Cho divides 4,800 into equal groups of 60. How many equal groups of 60 will Cho have?
=
–
24
92
23,065
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 7 Monday
Tuesday
1.
1.36
plus
0.76
=
1.
1.05
plus
0.75
=
2.
1.52
minus
0.82
is equal to
2.
2.06
minus
0.56
is equal to
3.
45,381
+
34,273
=
3.
45,053
+
29,371
=
4.
6
x
43
=
4.
5
x
29
=
5.
3
x
143
equals
5.
4
x
241
equals
6.
4
times
9
=
6.
6
times
8
=
7.
84
divided by
7
=
7.
36
divided by
6
=
8.
360
shared by
9
equals
8.
270
shared by
3
equals
9.
9 14 4 5
+
8 14
=
9.
+
9 15
=
of
15
is equal to
10.
9 15 4 12
of
60
is equal to
10.
Wednesday
Thursday
1.
1.09
plus
0.68
=
1.
1.45
plus
0.78
=
2.
2.15
minus
0.93
is equal to
2.
2.61
minus
1.82
is equal to
3.
23,367
+
21,094
=
3.
29,072
+
25,339
=
4.
6
x
54
=
4.
7
x
46
=
5.
7
x
154
equals
5.
8
x
325
equals
6.
7
times
6
=
6.
5
times
6
=
7.
48
divided by
4
=
7.
48
divided by
4
=
8.
720
shared by
8
equals
8.
140
shared by
7
equals
9.
10 15 7 11
+
13 15
=
9.
+
13 15
=
of
55
is equal to
10.
15 15 3 12
of
36
is equal to
10.
Friday 1.
1.67
plus
0.92
=
2.
2.56
minus
1.14
is equal to
3.
30,405
+
21,304
=
4.
8
x
63
=
5.
9
x
413
equals
6.
12
times
6
=
7.
32
divided by
8
=
8.
480
shared by
6
equals
9.
13 21 9 12
+
13 21
=
of
96
is equal to
10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 25
Ninja challenge
Tom has 1,470 fewer marbles than Iko. Iko has 2,606 marbles. How many marbles does Tom have?
25
15/09/2022 09:59
SHINOBI LEVEL
WEEK 7 Monday
Tuesday
1.
586,493
+
10,000
=
1.
838,034
+
10,000
=
2.
586,493
+
100,000
=
2.
838,034
+
100,000
=
3.
1
x
1
=
3.
2
x
2
=
4.
1²
is
equal
to
4.
2²
is
equal
to
5.
1
squared
is equal
to
5.
2
squared
is equal
to
6.
356
x
2
=
6.
838
x
2
=
7.
356
x
3
=
7.
838
x
3
=
8.
356
x
5
=
8.
838
x
5
=
9.
3 5
+
4 5 3 5
9.
6 8
+
3 8 7 8
=
10.
=
= +
6 5
10.
=
Wednesday
+
Thursday
1.
599,492
+
10,000
=
1.
209,493
+
10,000
=
2.
599,492
+
100,000
=
2.
209,493
+
100,000
=
3.
3
x
3
=
3.
4
x
4
=
4.
3²
is
equal
to
4.
4²
is
equal
to
5.
3
squared
is equal
to
5.
4
squared
is equal
to
6.
1,293
x
2
=
6.
3,492
x
2
=
7.
1,293
x
3
=
7.
3,492
x
3
=
8.
1,293
x
5
=
8.
3,492
x
5
=
9.
5 9
+
7 9 5 9
9.
8 11
+
7 11 9 11
=
10.
=
= +
5 9
1.
245,392
+
10,000
=
2.
245,392
+
100,000
=
3.
5
x
5
=
4.
5²
is
equal
to
5.
5
squared
is equal
to
6.
2,495
x
2
=
7.
2,495
x
3
=
8.
2,495
x
5
=
9.
6 13
+
7 13 11 13
=
=
26
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 26
+
10.
=
+
10 11
Ninja challenge
Friday
10.
5 8
Tom says that 1,000 less than 60,002 is equal to 59,020. Is Tom correct? Explain why.
9 13 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 7 Monday
Tuesday
1.
80,451 subtract 19,371
2.
=
28.45
add
14,284
=
4.
=
13.45
plus
12.34
5.
=
496
÷
3.
6.
17,273
6
7. 8. 9. 10.
3 4 2 4
times
1.
74,222 subtract 21,293
2.
=
36.52
add
17,867
=
4.
=
14.55
plus
9.65
4
5.
=
870
÷
5
=
210
6.
=
315
= minus 19.34
3.
÷
1,000
=
0.37
7.
x
100
equals
45
8.
add
2 4 1 5
+
=
9.
=
10.
21,077
7
3 6 2 3
Wednesday
5.76
6
5.
=
945
÷
7
=
455
6.
=
497
5.
=
936
÷
= minus 17.43
3.
÷
1,000
=
0.47
7.
x
100
equals
23
8.
add
5 6 1 4
=
9.
=
10.
1.
38,095 subtract 12,241
2.
=
41.54
add
15,108
=
4.
=
21.56
plus
9.89
5.
=
976
÷
8
=
525
7
times
= minus 18.65
7.
÷
1,000
=
0.75
8.
x
100
equals
71
add
5 7 3 8
=
9. 10.
5 7 2 4
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 27
32,670
7
5 7 2 4
times
= minus 16.31
÷
1,000
=
0.56
x
100
equals
28
add
3 7 1 3
=
+
=
Ninja challenge
Friday
6.
=
plus
8.32
27,834
+
19.56
plus
3.
=
=
17.44
+
add
4.
=
10.
17
=
4.
9.
equals
5 6 1 5
18,760
=
5 6 2 3
100
add
19,909
8.
x
39.53
add
7.
0.24
=
41.98
times
=
2.
=
7
1,000
56,100 subtract 13,477
2.
6.
÷
1.
61,204 subtract 20,371 30,879
minus 18.54
Thursday
1. 3.
times
=
If Iko counts on 310,000 from 90,003, what will her answer be?
= 27
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 8 Monday
Tuesday
1.
5.67
plus
4.92
=
1.
6.62
plus
5.16
=
2.
8.56
minus
4.42
is equal to
2.
8.89
minus
5.27
is equal to
3.
23,897
–
21,304
=
3.
27,364
–
19,384
=
4.
0.8
x
100
=
4.
0.2
x
100
=
5.
0.45
x
100
equals
5.
0.12
x
100
equals
6.
546
x
10
=
6.
206
x
10
=
7.
4.6
divided by
10
=
7.
1.9
divided by
10
=
8.
5
shared by
100
equals
8.
6
shared by
100
equals
9.
320
divided by
100
=
9.
560
divided by
100
=
10.
9 10
of
70
is equal to
10.
3 10
of
60
is equal to
Wednesday
Thursday
1.
8.72
plus
4.76
=
1.
9.15
plus
5.05
=
2.
9.36
minus
6.18
is equal to
2.
10.36
minus
5.31
is equal to
3.
45,273
–
23,149
=
3.
42,189
–
29,371
=
4.
0.1
x
100
=
4.
0.3
x
100
=
5.
0.78
x
100
equals
5.
0.61
x
100
equals
6.
314
x
10
=
6.
287
x
10
=
7.
4.1
divided by
10
=
7.
9.4
divided by
10
=
8.
9
shared by
100
equals
8.
6
shared by
100
equals
9.
290
divided by
100
=
9.
480
divided by
100
=
10.
3 7
10.
3 5
of
50
is equal to
of
42
is equal to
Friday 1.
11.45
plus
6.6
=
2.
12.56
minus
3.56
is equal to
3.
26,354
–
19,283
=
4.
0.8
x
100
=
5.
0.51
x
100
equals
6.
623
x
10
=
7.
8.6
divided by
10
=
8.
5
shared by
100
equals
9.
730
divided by
100
=
10.
3 8
of
48
is equal to
28
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 28
Ninja challenge
Sam says 1,600 is 1,200 less than 2,700. Is Sam correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 8 Monday
Tuesday
1.
=
486,604
+
10,000
1.
=
284,392
+
10,000
2.
=
486,604
+
100,000
2.
=
284,392
+
100,000
x
6
=
x
7
=
is
equal
to
is
equal
to
3.
6
4.
3.
7
6²
4.
squared
5.
49
is equal
to
5.
36
is equal
to
6.
343
x
2
=
6.
2,324
x
2
=
7.
343
x
3
=
7.
2,324
x
3
=
8.
343
x
5
=
8.
2,324
x
5
=
9.
8 9
+
4 9 7 9
9.
13 15
+
4 15 11 15
=
10.
=
= +
8 9
10.
=
Wednesday
7² squared
+
8 15
Thursday
1.
=
457,764
+
10,000
1.
=
192,394
+
10,000
2.
=
457,764
+
100,000
2.
=
192,394
+
100,000
x
8
=
x
9
=
is
equal
to
is
equal
to
3.
8
4.
3.
9
8²
4.
squared
5.
81
is equal
to
5.
64
is equal
to
6.
1,767
x
2
=
6.
4,657
x
2
=
7.
1,767
x
3
=
7.
4,657
x
3
=
8.
1,767
x
5
=
8.
4,657
x
5
=
9.
16 19
+
4 19 15 19
9.
13 20
+
11 20 3 20
=
10.
=
= +
11 19
Friday 1.
=
453,394
+
10,000
2.
=
453,394
+
100,000
x
10
=
is
equal
to
3.
10
4. 5.
100
is equal
to
6.
2,485
x
2
=
7.
2,485
x
3
=
8.
2,485
x
5
=
9.
19 23
+
11 23 19 23
=
10.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 29
10.
=
9² squared
+
24 20
Ninja challenge
Iko says that one quarter of 40,000 is equal to 5,000 x 2. Is Iko correct? Explain why.
10² squared
+
18 23 29
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 8 Monday 1.
47,381
2. 3.
– =
23,769
43.76
+
Tuesday =
34,108
1.
–
23.75
2.
=
38,094
3.
48,288
– =
25,767
52.98
+
=
38,015
–
23.71
=
39,370
4.
=
45.76
+
12.56
4.
=
46.03
+
15.78
5.
=
864
÷
6
5.
=
741
÷
3
=
435
6.
=
460
0.26
7.
÷
100
=
0.54
8.
x
1,000
=
90
+
7 9 1 4
=
13 4 9 or 1 9
6.
5
x
7.
÷
100
=
8.
x
1,000
=
60
+
5 9 2 8
=
10 1 9 or 1 9
9. 10.
3 4
–
9. 10.
=
5
2 3
Wednesday 1.
56,901
2. 3.
– =
26,761
49.89
+
x
–
=
Thursday =
42,517
1.
–
24.65
2.
=
41,873
3.
39,261
– =
28,704
51.08
+
=
22,784
–
19.87
=
44,311
4.
=
54.87
+
11.32
4.
=
45.88
+
15.42
5.
=
868
÷
4
5.
=
985
÷
5
=
492
6.
=
335
0.87
7.
÷
100
=
0.96
8.
x
1,000
=
230
+
7 9 2 10
=
10 1 9 or 1 9
6.
6
x
7.
÷
100
=
8.
x
1,000
=
140
+
7 9 2 4
=
11 2 9 or 1 9
9. 10.
4 5
–
Friday 1.
43,211
2. 3.
– =
29,511
59.65
+
=
24,388
–
23.11
=
46,223
4.
=
48.12
+
17.43
5.
=
940
÷
4
=
234
6.
6
x
7.
÷
100
=
0.49
8.
x
1,000
=
510
9.
+
7 9 2 3
=
15 6 9 or 1 9
10.
4 5
–
30
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 30
9. 10.
=
5
3 5
x
–
=
Ninja challenge
Cho adds an unknown number to 45,483 and gets an answer of 62,374. What is Cho’s unknown number?
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 9 Monday
Tuesday
1.
1,000 subtract
365
=
1.
1,000 subtract
936
=
2.
2,000
minus
745
is equal to
2.
2,000
minus
417
is equal to
3.
1
–
0.4
=
3.
1
–
0.1
=
4.
0.81
x
10
=
4.
0.32
x
10
=
5.
0.06
x
100
equals
5.
0.05
x
100
equals
6.
63
x
10
=
6.
87
x
10
=
7.
8.6
divided by
10
=
7.
1.7
divided by
10
=
8.
55
shared by
10
equals
8.
43
shared by
10
equals
9.
730
divided by
1,000
=
9.
610
divided by
1,000
=
10.
3 4
of
36
is equal to
10.
3 8
of
48
is equal to
Wednesday
Thursday
1.
1,000 subtract
213
=
1.
1,000 subtract
501
=
2.
2,000
minus
874
is equal to
2.
2,000
minus
481
is equal to
3.
2
–
0.3
=
3.
2
–
0.9
=
4.
0.57
x
10
=
4.
0.79
x
10
=
5.
0.09
x
100
equals
5.
0.04
x
100
equals
6.
91
x
10
=
6.
83
x
10
=
7.
8.9
divided by
10
=
7.
7.3
divided by
10
=
8.
78
shared by
10
equals
8.
46
shared by
10
equals
9.
920
divided by
1,000
=
9.
860
divided by
1,000
=
10.
7 8
10.
4 9
of
108
is equal to
of
16
is equal to
Friday 1.
1,000 subtract
824
=
2.
2,000
minus
194
is equal to
3.
3
–
0.4
=
4.
0.56
x
10
=
5.
0.03
x
100
equals
6.
67
x
10
=
7.
1.4
divided by
10
=
8.
12
shared by
10
equals
9.
170
divided by
1,000
=
10.
2 3
of
24
is equal to
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 31
Ninja challenge
Iko doubles 210. Tom halves 830. Who has more?
31
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 9 Monday
Tuesday
1.
305,493
–
10,000
=
1.
834,392
–
10,000
=
2.
305,493
–
100,000
=
2.
834,392
–
100,000
=
3.
11
x
11
=
3.
12
x
12
=
is
equal
to
11²
4.
is
equal
to
12²
is equal to
11
5.
is equal to
12
√121
6.
√144
4. 5.
The square
6.
root of
is
equal
to
The square
root of
is
equal
to
7.
1,485
x
6
=
7.
4,923
x
9
=
8.
1,485
x
8
=
8.
4,923
x
4
=
9.
12 9
–
4 9 15 9
9.
15 13
–
4 13 27 13
=
10.
=
= –
11 9
10.
=
Wednesday
–
12 13
Thursday
1.
495,592
–
10,000
=
1.
384,593
–
10,000
=
2.
495,592
–
100,000
=
2.
384,593
–
100,000
=
3.
10
x
10
=
3.
9
x
9
=
is
equal
to
10²
4.
is
equal
to
9²
is equal to
10
5.
is equal to
9
√100
6.
√81
4. 5.
The square
6.
root of
is
equal
to
The square
root of
is
equal
to
7.
3,493
x
6
=
7.
4,349
x
8
=
8.
3,493
x
4
=
8.
4,349
x
6
=
9.
25 20
–
4 20 30 20
9.
18 13
–
4 13 22 13
=
10.
=
= –
17 20
1.
319,302
–
10,000
=
2.
319,302
–
100,000
=
3.
8
x
8
=
is
equal
to
8²
is equal to
8 √64
5.
The square
6.
root of
is
equal
to
7.
2,492
x
4
=
8.
2,492
x
6
=
9.
20 11
–
6 11 17 11
=
10.
=
32
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 32
–
=
–
11 13
Ninja challenge
Friday
4.
10.
Tom says that the difference between 12,046 and 3,500 is 9,546. Is Tom correct? Explain why.
5 11 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 9 Monday
Tuesday
1.
=
302
÷
100
1.
=
413
÷
100
2.
=
4.6
x
10
2.
=
6.1
x
10
3.
x
1,000
=
810
3.
x
1,000
=
740
4.
÷
100
=
0.56
4.
÷
100
=
0.13
5.
=
1,032
÷
4
5.
=
1,072
÷
4
6.
=
5
x
1,342
6.
=
5
x
1,527
7.
÷
70
=
7
7.
÷
50
=
6
x
40
=
3,200
8.
x
20
=
1,600
–
7 9 1 3
–
5 9 1 3
=
8. 9. 10.
1 29 2 6
+
=
9.
=
10.
1 39 2 5
Wednesday
+
=
Thursday
1.
=
506
÷
100
1.
=
482
÷
100
2.
=
2.3
x
10
2.
=
5.6
x
10
3.
x
1,000
=
150
3.
x
1,000
=
850
4.
÷
100
=
0.45
4.
÷
100
=
0.27
5.
=
1,435
÷
5
5.
=
1,662
÷
6
6.
=
5
x
1,699
6.
=
6
x
1,048
7.
÷
90
=
7
7.
÷
80
=
6
x
40
=
2,800
8.
x
90
=
4,500
–
5 6 3 10
–
3 6 3 10
=
8. 9. 10.
1 36 2 5
+
=
9.
=
10.
Friday 1.
=
319
÷
100
2.
=
7.6
x
10
3.
x
1,000
=
610
4.
÷
100
=
0.33
5.
=
1,812
÷
6
6.
=
6
x
1,119
7.
÷
70
=
6
8.
x
90
=
6,300
–
6 7 3 10
=
9. 10.
1 17 1 20
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 33
1 16 1 2
+
=
Ninja challenge
Cho multiplies the product of 50 times 9 by 5. What answer does Cho have?
= 33
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 10 Monday 1.
5,000 subtract
2.
3,000
3.
Tuesday
364
=
1.
5,000 subtract
minus
1,190
is equal to
2.
3,000
3
–
0.7
=
3.
4.
24
x
100
=
5.
123
x
100
6.
67.6
x
7.
1,452
8.
938
=
minus
1,250
is equal to
4
–
1.1
=
4.
41
x
100
=
equals
5.
203
x
100
equals
10
=
6.
12.5
x
10
=
divided by
10
=
7.
1,573
divided by
10
=
736
shared by
10
equals
8.
173
shared by
10
equals
9.
1,500
divided by
100
=
9.
2,400
divided by
100
=
10.
2 7
of
35
is equal to
10.
6 7
of
42
is equal to
Wednesday
Thursday =
1.
6,000 subtract 2,305
1,313
is equal to
2.
4,000
minus
1,937
is equal to
–
3.2
=
3.
8
–
4.5
=
26
x
100
=
4.
33
x
100
=
5.
413
x
100
equals
5.
512
x
100
equals
6.
10.5
x
10
=
6.
16.7
x
10
=
7.
2,406
divided by
10
=
7.
1,284
divided by
10
=
8.
245
shared by
10
equals
8.
323
shared by
10
equals
9.
3,600
divided by
100
=
9.
1,700
divided by
100
=
10.
6 9
10.
7 12
of
144
is equal to
1.
5,000 subtract 1,523
2.
3,000
minus
3.
6
4.
of
54
is equal to
Friday 1.
6,000 subtract 3,475
2.
4,000
minus
2,714
is equal to
3.
9
–
6.7
=
4.
49
x
100
=
5.
672
x
100
equals
6.
24.5
x
10
=
7.
2,371
divided by
10
=
8.
445
shared by
10
equals
9.
2,300
divided by
100
=
10.
9 11
of
44
is equal to
34
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 34
=
=
Ninja challenge
Tom starts at the number 904. He starts counting on in hundreds. He counts on 8 lots of 100. What number does Tom reach?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 10 Monday
Tuesday
1.
=
467,593
–
10,000
1.
=
139,403
–
10,000
2.
=
458,593
–
100,000
2.
=
139,403
–
100,000
x
9
=
x
8
=
is
equal
to
9²
4.
is
equal
to
8²
is equal to
9
5.
is equal to
8
√81
6.
√64
3.
9
4. 5.
The square
6.
root of
is
equal
to
3.
8 The square
root of
is
equal
to
7.
2,394
x
4
=
7.
4,393
x
8
=
8.
2,394
x
6
=
8.
4,393
x
6
=
9.
16 11
–
7 11 15 11
9.
21 18
–
7 18 22 18
=
10.
=
= –
7 11
10.
=
Wednesday
–
5 18
Thursday
1.
=
453,595
–
10,000
1.
=
905,594
–
10,000
2.
=
453,595
–
100,000
2.
=
905,594
–
100,000
x
7
=
x
6
=
is
equal
to
7²
4.
is
equal
to
6²
is equal to
7
5.
is equal to
6
√49
6.
√36
3.
7
4. 5.
The square
6.
root of
is
equal
to
3.
6 The square
root of
is
equal
to
7.
3,495
x
4
=
7.
2,943
x
6
=
8.
3,495
x
6
=
8.
2,943
x
8
=
9.
35 21
–
8 21 29 21
9.
16 9
–
5 9 25 9
=
10.
=
= –
9 21
Friday 1.
=
400,695
–
10,000
2.
=
400,695
–
100,000
x
5
=
is
equal
to
5²
is equal to
5 √25
3.
5
4. 5.
The square
6.
root of
is
equal
to
7.
4,304
x
4
=
8.
4,304
x
8
=
9.
13 5
–
4 5 14 5
=
10.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 35
–
10.
=
–
14 9
Ninja challenge
Cho says that 40 groups of 90 is equal to 3,600. Is Cho correct? Explain why.
8 5 35
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 10 Monday 1.
3.15
2.
760
Tuesday
equals
divided by
100
1.
2.83
=
times
100
2.
510
multiplied by
1,000
=
shared by
100
=
5.
=
1,932
divided by
7
6.
equals
7
multiplied by
3. 4.
3,942
7.
420
÷
8.
70
times
9.
1 15 1 4
10.
subtract
add
4 5 3 8
equals
divided by
100
=
times
100 5,200
multiplied by
1,000
=
shared by
100
=
5.
=
1,995
divided by
7
1,206
6.
equals
7
multiplied by
1,069
=
6
7.
560
÷
=
7
=
6,300
8.
60
times
=
5,400
equals
9.
is equal to
10.
1 24 3 4
6,600
3. 4.
2,034
Wednesday
subtract
add
3 4 1 20
equals is equal to
Thursday
1.
1.83
equals
divided by
100
1.
7.82
equals
divided by
100
2.
670
=
times
100
2.
560
=
times
100
8,300
3.
1,900
3. 4.
1,905
5. 6.
multiplied by
1,000
=
shared by
100
=
=
2,037
divided by
7
multiplied by
1,089
6.
=
6
7.
540
÷
=
4,200
8.
40
times
equals
9.
is equal to
10.
1 59 3 5
equals
7.
360
÷
8.
60
times
9.
1 29 4 5
10.
subtract
add
8 9 1 20
4. 7
Friday 1.
8.14
2.
740
3. 4.
3,451
5. 6.
equals
divided by
100
=
times
100 2,600
multiplied by
1,000
=
shared by
100
=
=
2,672
divided by
8
8
multiplied by
1,434
equals
7.
840
÷
=
12
8.
80
times
=
5,600
9.
1 29
subtract
10.
3 4
add
8 9 1 10
36
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 36
2,041
5.
multiplied by
1,000
=
shared by
100
=
=
2,128
divided by
7
7
multiplied by
1,128
=
9
=
2,800
equals
subtract
add
7 9 1 10
equals is equal to
Ninja challenge
Tom has a total of 27,000. If Tom has 300 equal groups, what is each equal group made up of?
equals is equal to
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 11 Monday 1.
7,000 subtract 2,839
2.
2,000
minus
3.
4
4.
Tuesday =
1.
8,000 subtract 3,473
1,374
is equal to
2.
4,000
minus
2,370
is equal to
take away
1.32
=
3.
5
take away
3.21
=
27
times
100
=
4.
53
times
100
=
5.
650
multiplied by
100
equals
5.
120
multiplied by
100
equals
6.
6.6
times
100
=
6.
1.9
times
100
=
7.
650
divided by
100
=
7.
350
divided by
100
=
8.
45
shared by
100
equals
8.
27
shared by
100
equals
9.
12,300
divided by
100
=
9.
17,200
divided by
100
=
10.
4 6
of
30
is equal to
10.
4 7
of
21
is equal to
Wednesday
=
Thursday =
1.
8,000 subtract 1,472
3,037
is equal to
2.
9,000
minus
7,582
is equal to
take away
4.16
=
3.
8
take away
7.09
=
49
times
100
=
4.
61
times
100
=
5.
370
multiplied by
100
equals
5.
190
multiplied by
100
equals
6.
4.2
times
100
=
6.
7.1
times
100
=
7.
670
divided by
100
=
7.
590
divided by
100
=
8.
92
shared by
100
equals
8.
83
shared by
100
equals
9.
23,500
divided by
100
=
9.
45,600
divided by
100
=
10.
5 8
10.
7 8
of
96
is equal to
1.
6,000 subtract 5,173
2.
7,000
minus
3.
7
4.
of
72
is equal to
Friday 1.
5,000 subtract 2,374
2.
6,000
minus
4,084
is equal to
3.
9
take away
5.19
=
4.
53
times
100
=
5.
490
multiplied by
100
equals
6.
8.3
times
100
=
7.
640
divided by
100
=
8.
92
shared by
100
equals
9.
67,200
divided by
100
=
10.
9 11
of
99
is equal to
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 37
=
=
Ninja challenge
Cho says that 400 shared by 5 is equal to 240 shared by 3. Is Cho correct? Explain why.
37
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 11 Monday 1.
10,000
+
Tuesday =
304,493
1.
–
100,000
2.
684,294
=
10,000
–
=
754,493
+
100,000
2.
464,304
=
3.
1²
is equal to
1
x
3.
2²
is equal to
2
x
4.
2
squared
is equal
to
4.
3
squared
is equal
to
5.
The square
root of
The square
root of
6.
3
5.
√16
6.
is
equal
to
7
=
7.
=
7.
2,495
x
8.
2,495
x
9
9.
17 9
–
12 9 7 9
10.
is equal to
=
= +
11 9
10,000
+
4 √25
is
equal
to
1,395
x
8
=
8.
1,395
x
7
=
9.
13 10
–
5 10 7 10
=
10.
=
Wednesday 1.
is equal to
+
11 10
Thursday =
874,964
1.
–
10,000
=
869,075
–
100,000
2.
=
297,546
+
100,000
2.
234,329
=
3.
3²
is equal to
3
x
3.
4²
is equal to
4
x
4.
4
squared
is equal
to
4.
5
squared
is equal
to
5.
The square
root of
The square
root of
6.
is equal to
5
5.
√36
6.
is
equal
to
is equal to
6 √49
is
equal
to
7.
5,878
x
9
=
7.
4,878
x
7
=
8.
5,878
X
6
=
8.
4,878
x
5
=
9.
19 7
–
6 7 12 20
9.
23 17
–
3 17 15 16
=
10.
=
= +
15 20
Friday 1.
+
10,000
=
988,986
2.
=
547,872
–
100,000
3.
5²
is equal to
5
x
4.
6
squared
is equal
to
5.
The square
root of
6.
is equal to
7 √64
is
equal
to
7.
8,878
x
9
=
8.
8,878
x
7
=
9.
15 8
–
4 8 15 23
=
10.
=
38
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 38
+
10.
=
+
7 16
Ninja challenge
Sam says that the difference between 44,607 and 10,000 is 3,572. Is Sam correct? Explain why.
14 23 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 11 Monday 1.
equals 454.12
2.
=
3.
multiplied by
4.
12.4
Tuesday multiplied by
100
1.
times
1,000
2.
=
3.
multiplied by
170
1,000
=
184,290 shared by 1,000
=
4.
multiplied by
100
17.9
times
1,000
1,000
=
240
174,450 shared by 1,000
=
equals 172.74
5.
8,400
÷
70
=
5.
4,800
÷
60
=
6.
800
times
70
=
6.
300
times
70
=
7.
1 13 3 5
plus
equals
7. 8.
minus
5 7 1 4
equals
is equal to
1 17 4 5
plus
minus
2 3 4 15
9.
=
2,079
divided by
9
9.
=
2,925
divided by
9
10.
equals
9
multiplied by
1,465
10.
equals
9
multiplied by
1,503
multiplied by
100
8.
Wednesday 1.
equals 233.37
is equal to
Thursday multiplied by
100
1.
equals 364.06
2.
=
34.5
times
1,000
2.
=
56.3
times
1,000
3.
multiplied by
1,000
=
670
3.
multiplied by
1,000
=
810
345,060 shared by 1,000
=
4.
219,380 shared by 1,000
=
4. 5.
1,600
÷
20
=
5.
1,400
÷
20
=
6.
500
times
70
=
6.
700
times
70
=
7.
1 15
plus
equals
7.
1 27
plus
is equal to
8.
minus
6 7 2 3
equals
minus
4 5 1 4
=
2,934
divided by
=
3,069
divided by
9
9
multiplied by
9
multiplied by
1,604
8.
4 6
9. 10.
equals
9 1,578
Friday 1.
equals 419.26
multiplied by
100
2.
=
67.5
times
1,000
3.
multiplied by
1,000
=
920
380,460 shared by 1,000
=
4. 5.
2,700
÷
30
=
6.
800
times
70
=
7.
1 57 6 7
plus
equals
minus
6 7 7 14
9.
=
3,258
divided by
9
10.
equals
9
multiplied by
2,341
8.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 39
9. 10.
5 6
equals
is equal to
Ninja challenge
The answer to the question is 1,028. To get to the answer, Cho multiplied a number by 7, then doubled it and took away 400. What number did Cho start with?
is equal to
39
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 12 Monday
Tuesday
1.
19,000 subtract 12,479
=
1.
18,000 subtract 13,273
2.
14,000 minus 11,021
is equal to
2.
16,000 minus
=
9,704
is equal to
3.
12
take away
6.32
=
3.
13
take away
9.41
=
4.
53
times
10
=
4.
14
times
10
=
5.
490
multiplied by
10
equals
5.
230
multiplied by
10
equals
6.
8.3
times
10
=
6.
9.6
times
10
=
7.
640
divided by
10
=
7.
750
divided by
10
=
8.
92
shared by
10
equals
8.
83
shared by
10
equals
9.
67,200
divided by
10
=
9.
12,400
divided by
10
=
10.
23,457
+
19,276
=
10.
34,293
+
11,263
=
Wednesday
Thursday
1.
14,000 subtract 10,260
=
1.
17,000 subtract 15,370
=
2.
15,000 minus 11,280
is equal to
2.
16,000 minus 12,170
is equal to
3.
12
take away
8.38
=
3.
15
4.
51
times
10
=
4.
5.
190
multiplied by
10
equals
6.
7.4
times
10
7.
320
divided by
8.
23
9. 10.
take away
8.98
=
76
times
10
=
5.
150
multiplied by
10
equals
=
6.
9.9
times
10
=
10
=
7.
970
divided by
10
=
shared by
10
equals
8.
91
shared by
10
equals
19,700
divided by
10
=
9.
22,600
divided by
10
=
23,822
+
13,228
=
10.
30,070
+
25,098
=
Friday 1.
19,000 subtract 11,367
2.
12,000 minus
=
9,293
is equal to
3.
17
take away
11.26
=
4.
51
times
10
=
5.
630
multiplied by
10
equals
6.
6.7
times
10
=
7.
810
divided by
10
=
8.
66
shared by
10
equals
9.
41,100
divided by
10
=
10.
45,271
+
12,163
=
40
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 40
Ninja challenge
Sam creates 4 groups of 360. He says the total is equal to 12 times 120. Is Sam correct?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 12 Monday 1.
100
+
Tuesday =
687,593
1.
–
10,000
2.
352,405
=
–
1,000
=
852,596
+
10,000
2.
234,592
=
3.
6²
is equal to
6
x
3.
7²
is equal to
7
x
4.
7
squared
is equal
to
4.
8
squared
is equal
to
5.
The square
root of
The square
root of
is equal to
8
5.
is equal to
9
6.
is
equal
to
√81
6.
is
equal
to
√100
7.
=
3,932
x
4
7.
=
1,205
x
5
=
3,932
x
9
8.
=
1,205
x
7
+
12 11 46 39
+
11 12 46 30
=
8. 9.
13 11
10.
=
9.
= –
8 39
7 12
10.
=
Wednesday 1.
10,000
+
–
12 30
=
274,403
+
100,000
Thursday =
885,309
1.
+
1,000
2.
795,394
=
–
1,000
2.
793,493
=
3.
8²
is equal to
8
x
3.
9²
is equal to
9
x
4.
9
squared
is equal
to
4.
10
squared
is equal
to
5.
The square
root of
The square
root of
is equal to
10
5.
is equal to
11
6.
is
equal
to
√121
6.
is
equal
to
√144
7.
=
3,495
x
9
7.
=
3,564
x
5
=
3,495
x
7
8.
=
3,564
x
8
+
19 23 35 30
+
13 20 39 35
=
8. 9.
12 23
10.
=
9.
= –
8 30
Friday 1.
+
10,000
=
684,395
–
1,000
2.
784,393
=
3.
12²
is equal to
12
x
4.
11
squared
is equal
to
5.
The square
root of
is equal to
10
6.
is
equal
to
√81
7.
=
3,493
x
9
8.
=
3,493
x
7
+
15 21 43 30
=
9. 10.
18 21
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 41
–
10.
14 20
=
–
6 35
Ninja challenge
Cho says that one quarter of 3,600 is equal to 900. Is Cho correct? Explain why.
12 30 41
15/09/2022 09:59
v
13
GRAND MASTER LEVEL
WEEK 12 Monday 1.
=
14,684
Tuesday ÷
100
1.
x
100
2.
1,740
=
=
25,371
÷
100
x
100
2.
6,750
=
3.
0.92
x
100
=
3.
0.71
x
100
=
4.
380,400
÷
100
=
4.
230,400
÷
100
=
÷
30
=
÷
60
=
x
70
=
x
90
=
+
6 7 7 14
+
8 7 11 14
=
5. 6.
8
7.
5 7
8. 9. 10.
– 3 4 2 5
of of
250
9
=
5. 6.
8
7.
4 7
=
4 14
8.
=
180
9. 10.
=
– 3 4 2 5
Wednesday 1.
=
32,361
of of
500
=
2 14
=
270
=
Thursday ÷
100
1.
x
100
2.
3,060
=
=
40,627
÷
100
x
100
2.
2,390
=
3.
0.41
x
100
=
3.
0.29
x
100
=
4.
432,900
÷
100
=
4.
177,400
÷
100
=
÷
80
=
÷
80
=
5.
5
5.
6.
5
x
90
=
6.
6
x
50
=
7.
6 7
+
6 7 12 16
=
7.
6 12
+
9 12 9 16
=
8. 9. 10.
– 2 6 2 7
of of
280
=
3 16
8.
=
120
9. 10.
=
Friday 1.
=
29,982
÷
100
x
100
2.
5,630
=
3.
0.45
x
100
=
4.
305,600
÷
100
=
÷
70
=
x
50
=
+
4 12 2 16
=
5. 6.
8
7.
10 12
8. 9. 10.
– 4 5 5 8
of of
320
42
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 42
7
– 2 6 3 8
of of
400
9
=
1 16
=
240
=
Ninja challenge
If Tom has 900 groups of 800, how many does he have in total?
5
=
9 16
=
360
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 13 Monday
Tuesday
1.
40,000
–
12,364
=
1.
30,000
–
25,380
=
2.
20,000
–
6,482
is equal to
2.
20,000
–
11,270
is equal to
3.
20
–
9.13
=
3.
20
–
11.45
=
4.
0.56
x
10
=
4.
0.57
x
10
=
5.
27
x
10
equals
5.
34
x
10
equals
6.
0.5
x
10
=
6.
0.7
x
10
=
7.
8
÷
10
=
7.
1
÷
10
=
8.
6.1
÷
10
equals
8.
6.3
÷
10
equals
9.
0.8
÷
10
=
9.
0.4
÷
10
=
10.
12.5
+
1.45
=
10.
13.6
+
4.9
=
Wednesday
Thursday
1.
30,000
–
16,780
=
1.
50,000
–
21,630
=
2.
20,000
–
15,270
is equal to
2.
40,000
–
23,460
is equal to
3.
20
–
14.27
=
3.
20
–
16.72
=
4.
0.89
x
10
=
4.
0.43
x
10
=
5.
74
x
10
equals
5.
32
x
10
equals
6.
0.8
x
10
=
6.
0.3
x
10
=
7.
6
÷
10
=
7.
9
÷
10
=
8.
7.9
÷
10
equals
8.
5.6
÷
10
equals
9.
0.2
÷
10
=
9.
0.8
÷
10
=
10.
14.8
+
7.6
=
10.
21.4
+
8.9
=
Friday 1.
60,000
–
34,273
=
2.
40,000
–
35,371
is equal to
3.
20
–
19.93
=
4.
0.29
x
10
=
5.
83
x
10
equals
6.
0.7
x
10
=
7.
6
÷
10
=
8.
4.8
÷
10
equals
9.
0.1
÷
10
=
10.
24.6
+
10.6
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 43
Ninja challenge
Iko is thinking of a number. She says her number is equal to 9 groups of 70. What number is Iko thinking of?
43
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 13 Monday
Tuesday
1.
456,304
+
34,503
=
1.
245,493
+
13,964
=
2.
446,304
+
24,503
=
2.
215,493
+
33,964
=
3.
6
x
10
=
3.
8
x
10
=
4.
6
x
100
=
4.
8
x
100
=
5.
6
x
1,000
=
5.
8
x
1,000
=
6.
24
÷
8
=
6.
12
÷
3
=
7.
240
÷
8
=
7.
120
÷
3
=
8.
1 8 3 4 3 4
8.
1 3 2 5 4 5
of
120
=
+
3 10 3 10
=
9. 10.
of
240
+
1 8 3 8
+
= =
9.
=
10.
Wednesday
+
=
Thursday
1.
124,664
+
19,694
=
1.
765,305
+
134,324
=
2.
127,664
+
29,694
=
2.
465,305
+
126,324
=
3.
9
x
10
=
3.
3
x
10
=
4.
9
x
100
=
4.
3
x
100
=
5.
9
x
1,000
=
5.
3
x
1,000
=
6.
18
÷
9
=
6.
15
÷
3
=
7.
180
÷
9
=
7.
150
÷
3
=
8.
1 9 2 3 2 3
of
180
=
8.
of
150
=
+
1 6 5 6
1 3 1 3 2 3
+
5 12 5 12
=
9. 10.
+
=
9.
=
10.
Friday 1.
425,385
+
321,596
=
2.
225,385
+
324,596
=
3.
7
x
10
=
4.
7
x
100
=
5.
7
x
1,000
=
6.
30
÷
5
=
7.
300
÷
5
=
8.
1 5 1 4 1 4
of
300
=
+
5 8 7 8
=
9. 10.
+
44
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 44
+
=
Ninja challenge
Iko says that 452 groups of 3 is equal to 1,206. Is Iko correct? Explain why.
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 13 Monday 1. 2.
60,040
= 50
=
Tuesday ÷
100
1.
x
1,000
2.
= 40
50,060
=
÷
100
x
1,000
3.
x
1,000
=
360
3.
x
1,000
=
270
4.
÷
1,000
=
300
4.
÷
1,000
=
120
5.
÷
70
=
500
5.
÷
70
=
700
x
50
=
x
90
=
add
4 12 9 16
add
8 12 3 16
=
6.
80
7.
11 12 11 16 4 5 3 4
8. 9. 10.
plus of
6.
80
=
7.
=
8.
10 12 15 16 4 7 3 5
=
of
3,200
280
9. 10.
=
Wednesday 1. 2.
30,050
= 10
=
plus of of
= =
3,500
360
=
Thursday ÷
100
1.
x
1,000
2.
= 60
90,040
=
÷
100
x
1,000
3.
x
1,000
=
690
3.
x
1,000
=
520
4.
÷
1,000
=
560
4.
÷
1,000
=
810
5.
÷
90
=
900
5.
÷
90
=
300
6.
30
x
90
=
6.
60
x
90
=
7.
10 13 8 9 4 9 5 9
add
12 13 7 9
=
7.
add
8.
12 17 3 9
=
=
11 17 8 9 4 9 5 7
8. 9. 10.
plus of
=
of
8,100
120
10.
=
Friday 1. 2.
= 50
40,030
=
÷
100
x
1,000
3.
x
1,000
=
910
4.
÷
1,000
=
360
5.
÷
80
=
800
x
90
=
add
12 17 5 9
=
6.
10
7.
15 17 8 9 4 7 5 8
8. 9. 10.
plus of of
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 45
of of
= =
4,200
200
=
Ninja challenge
Tom adds an unknown number to 104,594 and gets an answer of 170,388. What is Tom’s unknown number?
= =
1,600
9.
plus
280
= 45
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 14 Monday
Tuesday
1.
81
÷
9
=
1.
49
÷
7
=
2.
180
÷
6
=
2.
270
÷
3
=
3.
420
÷
60
=
3.
250
÷
50
=
4.
0.31
x
10
=
4.
0.32
x
10
=
5.
45
x
100
equals
5.
76
x
100
equals
6.
5.4
÷
10
equals
6.
2.5
÷
10
equals
7.
76
÷
100
=
7.
92
÷
100
=
8.
4
x
46
=
8.
5
x
56
=
9.
7
x
163
=
9.
6
x
274
=
10.
3
x
253
=
10.
4
x
251
=
Wednesday
Thursday
1.
64
÷
8
=
1.
144
÷
12
=
2.
320
÷
4
=
2.
720
÷
8
=
3.
360
÷
90
=
3.
120
÷
20
=
4.
0.69
x
10
=
4.
0.43
x
10
=
5.
12
x
100
equals
5.
93
x
100
equals
6.
3.4
÷
10
equals
6.
7.1
÷
10
equals
7.
84
÷
100
=
7.
96
÷
100
=
8.
7
x
78
=
8.
8
x
66
=
9.
5
x
232
=
9.
4
x
361
=
10.
3
x
547
=
10.
7
x
381
=
Friday 1.
132
÷
12
=
2.
540
÷
6
=
3.
450
÷
90
=
4.
0.17
x
10
=
5.
56
x
100
equals
6.
8.5
÷
10
equals
7.
74
÷
100
=
8.
3
x
78
=
9.
6
x
564
=
10.
9
x
253
=
46
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 46
Ninja challenge
Tom counts on 1,901 more than 1,320. What answer does he get?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 14 Monday
Tuesday
1.
=
134,504
+
76,594
1.
=
356,504
+
124,213
2.
=
124,504
+
376,594
2.
=
246,504
+
126,213
3.
5.6
x
10
=
3.
6.3
x
10
=
4.
5.6
x
100
=
4.
6.3
x
100
=
5.
5.6
x
1,000
=
5.
6.3
x
1,000
=
6.
45
÷
5
=
6.
48
÷
6
=
7.
450
÷
5
=
7.
480
÷
6
=
8.
1 5 2 5 4 5
8.
1 6 2 5 4 5
of
4,800
=
+
4 10 4 10
=
9. 10.
of
4,500
+
4 15 4 15
+
= =
9.
=
10.
Wednesday
+
=
Thursday
1.
=
475,394
+
53,486
1.
=
394,394
+
144,313
2.
=
535,394
+
154,486
2.
=
274,394
+
146,313
3.
7.1
x
10
=
3.
0.89
x
10
=
4.
7.1
x
100
=
4.
0.89
x
100
=
5.
7.1
x
1,000
=
5.
0.89
x
1,000
=
6.
42
÷
7
=
6.
44
÷
11
=
7.
420
÷
7
=
7.
440
÷
11
=
8.
1 7 1 3 2 3
of
4,200
=
8.
of
4,400
=
+
4 9 7 9
1 11 1 3 1 3
+
5 12 11 12
=
9. 10.
+
=
9.
=
10.
Friday 1.
=
456,604
+
19,008
2.
=
466,604
+
117,008
3.
0.93
x
10
=
4.
0.93
x
100
=
5.
0.93
x
1,000
=
6.
56
÷
8
=
7.
560
÷
8
=
8.
1 8 1 4 3 4
of
5,600
=
+
5 12 5 12
=
9. 10.
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 47
+
=
Ninja challenge
Iko shares 27,000 counters equally into 3 groups. How many counters will be in each group?
= 47
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 14 Monday 1. 2. 3.
add 5 6 2 6
4. 5. 6.
9. 10.
add plus
4 7 5 8
7. 8.
subtract
of of
5 6
3.
= =
12 3 9 or 1 9
4.
=
28
5.
=
10
6.
=
7. 9.
=
of
=
80
3,600
1.
add
2.
=
minus of
12 17
=
3 17 7 9
subtract 12 9 4 7 5 6
3 6 1 2 1 4 5 9
Tuesday
8. 10.
=
plus 2 5 5 7 4 6 5 9
1.
add
2.
plus
3. 4. 5. 6.
3 5 5 6 4 12 5 9
7. 8. 9. 10.
add subtract
15 9 4 5 5 7
=
14 9 4 9 5 8
=
15 6 9 or 1 9
3.
=
4.
of
=
60
6.
=
7. 9.
minus
=
7 11 8 9
of
=
440
add
2. 3. 4. 5. 6.
plus 3 6 5 8 6 7 2 8
7. 8. 9. 10.
add subtract
of of subtract
13 9 2 5 5 9
6 10 13 15 3 10 1 4
10 19
= =
8 4 10 or 5 22 7 15 or 115
=
36
=
24
=
2 19
of
=
180
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 48
16
=
20
=
5 17
of
=
320
of
2,400
=
3 5 4 6 4 10 2 6
add subtract
= =
12 4 15 or 5 23 11 12 or 112
= =
of
=
48
of
=
18
=
8 13
subtract 10 9 2 3 5 6
9 15 13 12 3 10 1 12
3 13
minus
=
3 1 9 or 3
of
=
180
of
4,800
=
Ninja challenge
Iko doubles 60,000 and then quarters the answer. What number does Iko finish with?
=
3 1 9 or 3
48
=
=
= 8,100
8. 10.
=
minus of
=
3 1 9 or 3
plus
=
Friday 1.
=
=
2.
5.
8,400
11 17
=
8 4 10 or 5 10 1 9 or 1 9
minus
add
16
of
of
1.
= 3 11
of
=
Thursday 9 10
of subtract
subtract
subtract
Wednesday 6 10 5 9 1 15 1 3
add
6 10 5 9 2 4 1 2
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 15 Monday
Tuesday
1.
77
÷
7
=
1.
48
÷
8
=
2.
270
÷
3
is equal to
2.
420
÷
6
is equal to
3.
640
÷
80
=
3.
490
÷
70
=
4.
0.17
x
100
=
4.
0.54
x
100
=
5.
56
x
10
equals
5.
17
x
10
equals
6.
18
÷
100
equals
6.
24
÷
100
equals
7.
7
x
6
=
7.
5
x
9
=
8.
3
x
7
=
8.
12
x
11
=
9.
7
x
51
=
9.
6
x
67
=
10.
8
x
255
=
10.
9
x
189
=
Wednesday
Thursday
1.
27
÷
9
=
1.
21
÷
7
=
2.
240
÷
6
is equal to
2.
350
÷
7
is equal to
3.
280
÷
40
=
3.
450
÷
50
=
4.
0.94
x
100
=
4.
0.81
x
100
=
5.
45
x
10
equals
5.
63
x
10
equals
6.
37
÷
100
equals
6.
43
÷
100
equals
7.
6
x
9
=
7.
8
x
9
=
8.
9
x
12
=
8.
8
x
12
=
9.
7
x
62
=
9.
4
x
67
=
10.
5
x
624
=
10.
8
x
305
=
Friday 1.
36
÷
6
=
2.
810
÷
9
is equal to
3.
720
÷
90
=
4.
0.45
x
100
=
5.
78
x
10
equals
6.
39
÷
100
equals
7.
6
x
9
=
8.
12
x
7
=
9.
6
x
45
=
10.
9
x
143
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 49
Ninja challenge
Tom listens to a song that is 2.35 minutes long. Sam listens to a song that is 2.17 minutes long. Altogether, how long were Tom and Sam listening to songs?
49
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 15 Monday
Tuesday
1.
457,405
–
23,495
=
1.
273,293
–
86,694
=
2.
547,405
–
124,495
=
2.
293,293
–
185,694
=
3.
5
÷
10
=
3.
7
÷
10
=
4.
5
÷
100
=
4.
7
÷
100
=
5.
5
÷
1,000
=
5.
7
÷
1,000
=
6.
6
÷
2
=
6.
20
÷
5
=
7.
60
÷
2
=
7.
200
÷
5
=
8.
1 2 3 4 3 4
8.
1 5 7 8 7 8
of
2,000
=
–
1 4 3 4
=
9. 10.
of
60,000
–
5 12 7 12
–
= =
9.
=
10.
Wednesday
–
=
Thursday
1.
495,394
–
183,234
=
1.
745,604
–
345,593
=
2.
385,394
–
184,234
=
2.
955,604
–
343,593
=
3.
9
÷
10
=
3.
8
÷
10
=
4.
9
÷
100
=
4.
8
÷
100
=
5.
9
÷
1,000
=
5.
8
÷
1,000
=
6.
21
÷
3
=
6.
27
÷
9
=
7.
210
÷
3
=
7.
270
÷
9
=
8.
1 3 4 5 4 5
of
210,000
=
8.
of
27,000
=
–
1 10 7 10
1 9 3 4 3 4
–
5 12 6 12
=
9. 10.
–
=
9.
=
10.
Friday 1.
485,359
–
265,124
=
2.
265,359
–
262,124
=
3.
3
÷
10
=
4.
3
÷
100
=
5.
3
÷
1,000
=
6.
36
÷
4
=
7.
360
÷
4
=
8.
1 4 2 5 4 5
of
360,000
=
–
5 15 5 15
=
9. 10.
–
50
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 50
–
=
Ninja challenge
Tom shares 20,000 by 4,000. What answer does Tom have?
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 15 Monday 1.
=
2.
=
3.
equals
4.
=
5.
is equal to
6.
=
7.
equals
8.
=
9.
equals
10.
=
4 10 11 15 4 10 3 4 2 7 5 8 18 19 16 9 2 6 5 6
Tuesday 1.
=
2.
=
3.
equals
–
2 10 7 15 2 6 5 8
4.
=
of
49
5.
is equal to
of
48
6.
=
–
7.
equals
–
12 19 9 9
8.
=
of
120
9.
equals
of
4,200
10.
=
+
1.
=
2.
=
3.
equals
–
3 14 4 5 1 2 2 3
4.
=
of
48
5.
is equal to
of
36
6.
=
–
7.
equals
–
4 14 10 9
8.
=
of
56
9.
equals
of
4,500
10.
=
+ + +
Wednesday 1.
=
2.
=
3.
equals
4.
=
5.
is equal to
6.
=
7.
equals
8.
=
9.
equals
10.
=
10 14 4 5 1 7 4 5 3 4 5 12 13 14 15 9 5 7 7 9
=
2.
=
3.
equals
4.
=
5.
is equal to
6.
=
7.
equals
8.
=
9.
equals
10.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 51
2 9 3 7 2 5 5 7 5 6 6 9 5 8 17 9 6 9 3 7
–
2 12 8 16 2 6 2 8
of
40
of
63
– –
9 19 10 9
of
60
of
2,400
+
–
3 7 6 7 1 2 1 6
of
45
of
44
– –
4 8 14 9
of
140
of
2,400
+ + +
Thursday + +
Friday 1.
9 12 9 16 1 4 3 4 3 8 5 9 13 19 13 9 2 5 7 8
–
5 9 6 7 1 4 4 7
of
54
of
36
– –
4 8 10 9
of
360
of
6,300
+ + +
3 7 4 7 1 4 5 6 3 5 5 11 7 8 16 9 6 7 7 8
+ +
Ninja challenge
Sam says that if he doubles the numbers 135 and 136, the difference between the answers is 2. Is Sam correct? Explain why.
51
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 16 Monday
Tuesday
1.
72
÷
8
=
1.
48
÷
8
=
2.
84
÷
3
=
2.
93
÷
3
=
3.
126
÷
2
=
3.
112
÷
2
=
4.
0.04
x
1,000
=
4.
0.14
x
1,000
=
5.
45
÷
100
=
5.
71
÷
100
=
6.
48
÷
6
=
6.
36
÷
6
=
7.
6
x
7
=
7.
12
x
7
=
8.
5
x
12
=
8.
8
x
9
=
9.
3
x
87
=
9.
4
x
65
=
10.
5
x
206
=
10.
6
x
216
=
Wednesday
Thursday
1.
49
÷
7
=
1.
24
÷
6
=
2.
99
÷
3
=
2.
69
÷
3
=
3.
164
÷
2
=
3.
182
÷
2
=
4.
0.08
x
1,000
=
4.
0.34
x
1,000
=
5.
17
÷
100
=
5.
64
÷
100
=
6.
54
÷
6
=
6.
28
÷
4
=
7.
8
x
7
=
7.
5
x
7
=
8.
3
x
9
=
8.
6
x
9
=
9.
5
x
73
=
9.
6
x
74
=
10.
7
x
312
=
10.
8
x
253
=
Friday 1.
48
÷
4
=
2.
75
÷
3
=
3.
246
÷
2
=
4.
0.06
x
1,000
=
5.
83
÷
100
=
6.
16
÷
4
=
7.
12
x
11
=
8.
11
x
9
=
9.
9
x
56
=
10.
3
x
485
=
52
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 52
Ninja challenge
Iko finds 1,820 books in the library that are red. Cho looks for green books and finds half the amount Iko does. How many green books does Cho find?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 16 Monday
Tuesday
1.
=
338,593
–
264,234
1.
=
764,933
–
135,604
2.
=
848,593
–
261,234
2.
=
554,933
–
136,604
3.
53
÷
10
=
3.
67
÷
10
=
4.
53
÷
100
=
4.
67
÷
100
=
5.
53
÷
1,000
=
5.
67
÷
1,000
=
6.
28
÷
4
=
6.
35
÷
7
=
7.
280
÷
4
=
7.
350
÷
7
=
8.
1 4 4 5 4 5
8.
1 7 11 12 11 12
of
35,000
=
–
3 4 1 4
=
9. 10.
of
28,000
–
3 20 7 20
–
= =
9.
=
10.
Wednesday
–
=
Thursday
1.
=
653,594
–
98,623
1.
=
573,694
–
183,593
2.
=
783,594
–
194,623
2.
=
685,694
–
183,593
3.
98
÷
10
=
3.
52
÷
10
=
4.
98
÷
100
=
4.
52
÷
100
=
5.
98
÷
1,000
=
5.
52
÷
1,000
=
6.
72
÷
8
=
6.
77
÷
7
=
7.
720
÷
8
=
7.
770
÷
7
=
8.
1 8 19 25 19 25
of
72,000
=
8.
of
77,000
=
–
1 5 3 5
1 7 5 6 5 6
–
5 18 8 18
=
9. 10.
–
=
9.
=
10.
Friday 1.
=
583,592
–
134,113
2.
=
693,593
–
138,113
3.
25
÷
10
=
4.
25
÷
100
=
5.
25
÷
1,000
=
6.
88
÷
11
=
7.
880
÷
11
=
8.
1 11 4 5 4 5
of
88,000
=
–
11 20 12 20
=
9. 10.
–
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 53
–
=
Ninja challenge
Cho finds the difference between 65,095 and 12,475. What answer does Cho get?
= 53
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 16 Monday 1.
Tuesday more than less than
=
189,264
2.
=
145,809
3.
less than
more than less than
8.9
=
4.
=
0.19
times
1,000
100
5.
=
23.5
÷
100
6.
=
7.
equals
+
4 8 2 4
of
36
8.
=
7 8 2 5 3 4 4 6 4 5
+
+
5 7 2 4
of
32
303,232
1.
302,183
=
318,214
2.
=
293,274
3.
less than
9.4
=
4.
=
0.41
times
1,000
5.
=
14.9
÷
6.
=
+
7.
equals
8.
=
6 7 2 6 3 9 4 5 2 3
5.56
9.
280
equals
10.
1,200
=
4.59
of
9.
360
equals
of
10.
2,000
=
Wednesday 1.
=
361,274
2.
=
223,711
less than
11.5
=
4.
=
0.48
times
1,000
5.
=
30.8
÷
100
6.
=
+
7.
equals
+
6 8 3 12
8.
=
7 8 4 6 3 7 8 9 4 7
of
35
6.43
9.
560
equals
10.
3,200
=
=
561,026
457,578
2.
=
301,566
less than
more than less than
15.2
=
4.
=
0.71
times
1,000
5.
=
41.4
÷
100
6.
=
+
7.
equals
+
6 15 5 18
8.
=
10 15 3 6 3 9 8 9 6 7
of
54
3.
9.
240
equals
of
10.
7,200
=
2.
=
334,607
3.
less than
more than less than
17.4
=
4.
=
0.85
times
1,000
5.
=
57.3
÷
100
6.
=
+
7.
equals
+
9 15 5 12
8.
=
11 15 3 6 3 10 8 10 6 10
of
90
640
equals
10.
4,200
=
54
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 54
7.65
of
248,366
9.
of
1.
= 8.79
of
173,748
Friday 1.
278,809
Thursday more than less than
3.
253,271
187,274 502,677
102,364 399,879
of of
Ninja challenge
Cho starts with the number 15,671. She finishes with 1,005. How much did Cho subtract to get to 1,005?
of of Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 17 Monday +
2.
6 7 15 16
3.
Tuesday =
1.
–
2 7 10 16
+
2.
5 7 14 16
=
–
5 7 12 16
=
10,000
–
4,834
=
3.
10,000
–
1,263
=
4.
64
÷
4
=
4.
84
÷
4
=
5.
310
÷
5
=
5.
465
÷
5
=
6.
0.97
x
100
=
6.
0.35
x
100
=
7.
8
÷
100
=
7.
12
÷
100
=
8.
16
÷
4
=
8.
32
÷
4
=
9.
7
x
52
=
9.
7
x
28
=
10.
6
x
154
=
10.
6
x
178
=
1.
+
+
2.
9 9 17 19
3.
1.
Wednesday
=
Thursday =
1.
–
5 9 12 19
=
2.
9 9 18 19
=
–
7 9 10 19
10,000
–
2,046
=
3.
10,000
–
2,046
=
4.
96
÷
4
=
4.
60
÷
4
=
5.
295
÷
5
=
5.
605
÷
5
=
6.
0.41
x
100
=
6.
0.9
x
100
=
7.
31
÷
100
=
7.
27
÷
100
=
8.
56
÷
7
=
8.
40
÷
5
=
9.
8
x
43
=
9.
7
x
38
=
10.
6
x
340
=
10.
9
x
261
=
Friday +
2.
10 12 10 11
=
–
9 12 4 11
3.
10,000
–
3,171
=
4.
68
÷
4
=
5.
715
÷
5
=
6.
0.11
x
100
=
7.
46
÷
100
=
8.
36
÷
3
=
9.
8
x
43
=
10.
7
x
231
=
1.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 55
=
=
Ninja challenge
Sam says that if he adds 1,000, 3,000, 2,000 and 3,000 then he will have a number larger than 10,000. Is Sam correct?
55
15/09/2022 09:59
4 of 60
v
SHINOBI LEVEL
WEEK 17 Monday 1.
+
243,293
Tuesday =
699,785
1.
–
475,392
2.
499,807
=
3.
6
x
1,000
=
=
6
÷
2.
273,283
=
3.
4
x
10
=
=
4
÷
4.
10
–
4.
284,594
=
301,999
+
124,384
5.
4
÷
100
=
5.
6
x
100
=
6.
1 5 3 5 3 5 3 4 1 4
of
15
=
6.
of
35
=
of
15
=
7.
of
35
=
of
150
=
8.
of
350
=
–
7 12 11 12
1 5 3 5 3 5 4 5 3 5
–
7 15 11 15
=
7. 8. 9. 10.
+
=
9.
=
10.
Wednesday 1.
+
98,493
=
692,887
1.
–
98,493
2.
596,293
=
3.
2
x
10
=
=
2
÷
484,990
=
3.
9
x
100
=
=
9
÷
÷
10
=
5.
9
6.
1 6 5 6 5 6 2 3 1 3
7. 8. 9. 10.
1,000
1.
48
=
of
4,800
=
–
7 20 7 20
=
=
8.
–
=
9.
=
10.
–
85,493
x
100
=
=
55
÷
5.
55
÷
10
=
6.
1 8 7 8 7 8 2 3 2 3
of
16
=
of
16
=
of
1,600
=
–
5 18 5 18
=
10.
of
5 9 7 9
55
9.
=
4,200
3.
8.
48
of
=
7.
of
7.
467,423
4.
=
=
2.
+
56
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 56
253,485
1,000
42
562,917
+
÷
of
=
342,909
1 6 5 6 5 6 3 4 3 4
6.
87,493
=
2
=
+
253,485
5.
42
Friday
–
4.
of
+
=
Thursday
2. 4.
+
100
+
10
=
Ninja challenge
Iko says that 13,544 is 4,834 more than 9,985. Is Iko correct? Explain why.
100
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 17 Monday 1.
383,750
2.
237,316
= =
109,771
more than
3.
7.9
Tuesday more than less than
279,366
=
19.24
3.
1.
393,420
2.
102,016
=
154,697
more than
more than less than
8.2
=
20.87
=
189,645
4.
1,200
=
times
1,000
4.
3,600
=
times
1,000
5.
5.7
=
÷
1,000
5.
1.3
=
÷
1,000
plus
6.
=
plus
subtract
9 15 2 12
7.
equals
subtract
9 17 7 16
of
50
8.
=
of
60
of
600
9.
equals
of
700
of
3,000
10.
=
of
4,000
133,263
6.
=
7.
equals
8.
=
9.
equals
10.
=
14 15 5 6 6 10 7 10 9 10
Wednesday
Thursday
1.
585,844
=
2.
154,528
=
221,561
more than
more than less than
9.7
=
23.13
3.
times
1,000
4.
6,100
=
÷
1,000
5.
4.1
=
plus
6.
=
subtract
9 11 2 8
7.
equals
of
40
8.
=
of
200
9.
equals
of
9,000
10.
=
3. 4.
4,800
=
5.
2.7
=
6.
=
7.
equals
8.
=
9.
equals
10.
=
10 11 3 4 9 10 9 10 8 10
349,073
Friday 1.
531,137
2.
105,829
3.
=
172,572
more than
more than less than
8.3
=
21.71
=
121,525
4.
4,700
=
times
1,000
5.
9.6
=
÷
1,000
plus subtract
8 9 3 10
of
50
of
900
of
7,000
6.
=
7.
equals
8.
=
9.
equals
10.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 57
7 9 4 5 7 10 9 10 8 10
20 17 7 8 9 10 5 10 4 10
1.
554,537
=
2.
79,378
=
179,045
more than
more than less than
7.6
=
23.21
times
1,000
÷
1,000
plus subtract
9 11 2 10
of
80
of
700
of
8,000
8 11 3 5 7 10 6 10 5 10
Ninja challenge
Iko says that the total of 94,594 and 28,384 is 122,364. Is Iko correct? Explain why.
57
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 18 Monday 2.
5 6 9 12
3.
Tuesday equals
1.
minus
5 6 4 12
2.
5 6 10 12
equals
minus
3 6 5 12
=
1,000
–
16
equals
3.
1,000
–
305
equals
4.
4.75
–
1.23
=
4.
6.12
–
4.84
=
5.
16
–
1.4
=
5.
12
–
4.2
=
6.
224
shared by
4
=
6.
248
shared by
4
=
7.
270
divided by
6
=
7.
348
divided by
6
=
8.
5
times
62
=
8.
5
times
71
=
9.
8
x
108
=
9.
7
x
208
=
10.
522,482
+
123,374
=
10.
405,371
+
75,805
=
1. 2.
6 7 13 15
3.
1.
plus
Wednesday
plus
=
Thursday equals
1.
minus
3 7 11 15
=
2.
5 7 14 15
equals
minus
6 7 9 15
1,000
–
469
equals
3.
1,000
–
617
equals
4.
8.85
–
2.35
=
4.
9.17
–
1.98
=
5.
14
–
6.7
=
5.
15
–
3.7
=
6.
292
shared by
4
=
6.
308
shared by
4
=
7.
372
divided by
6
=
7.
426
divided by
6
=
8.
5
times
75
=
8.
6
times
76
=
9.
7
x
315
=
9.
8
x
311
=
10.
307,067
+
90,045
=
10.
208,001
+
70,893
=
plus
Friday 2.
8 9 18 19
equals
minus
8 9 14 19
3.
1,000
–
806
equals
4.
8.36
–
2.67
=
5.
17
–
6.9
=
6.
332
shared by
4
=
7.
468
divided by
6
=
8.
7
times
81
=
9.
8
x
353
=
10.
101,110
+
10,111
=
1.
plus
58
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 58
=
plus
=
Ninja challenge
Iko counts on 70 from 589. What number does Iko count on to?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 18 Monday 1.
+
123,394
Tuesday =
507,887
1.
–
264,493
2.
417,495
=
3.
576
x
100
=
=
576
÷
2.
139,394
=
3.
345
x
10
=
=
345
÷
4.
100
–
4.
86,548
=
386,947
+
74,548
5.
345
÷
10
=
5.
576
÷
1,000
=
6.
1 9 7 9 7 9 17 18 17 18
of
36
=
6.
of
36
=
of
36
=
7.
of
36
=
of
3,600
=
8.
of
3,600
=
–
2 9 2 9
1 12 5 12 5 12 11 12 11 12
–
3 4 3 4
=
7. 8. 9. 10.
+
=
9.
=
10.
Wednesday 1.
+
344,483
=
543,077
1.
–
424,483
2.
464,394
=
3.
390
x
100
=
=
390
÷
98,594
=
3.
809
x
10
=
=
809
÷
÷
100
=
5.
809
6.
1 4 3 4 3 4 9 10 9 10
7. 8. 9. 10.
10
1.
72
=
of
7,200
=
–
2 5 2 5
=
=
8.
–
=
9.
=
10.
–
245,493
x
1,000
=
=
607
÷
5.
607
÷
100
=
6.
1 11 7 11 7 11 13 16 13 16
of
88
=
of
88
=
of
88,000
=
–
5 8 5 8
=
10.
of
3 5 3 5
607
9.
=
2,400
3.
8.
72
of
=
7.
of
7.
387,485
4.
=
=
2.
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 59
110,040
1,000
24
542,978
+
÷
of
=
220,040
1 8 3 8 3 8 13 15 13 15
6.
67,485
=
390
=
+
264,354
5.
24
Friday
–
4.
of
+
=
Thursday
2. 4.
+
10
+
100
=
Ninja challenge
Iko says that 10,000 less than 39,005 is greater than 10,000 more than 19,005. Is Iko correct? Explain why.
10
= 59
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 18 Monday
Tuesday more than less than
1.
556,923
2.
293,456
=
105,377
3.
6
multiplied by
more than less than
1,326
=
10
4.
1,143
=
times
10
÷
100
5.
0.72
=
÷
100
add
3 4 2 3
6.
5 1 4 or 1 4
=
add
3 4 2 4
1.
530,624
2.
194,636
=
3.
4
multiplied by
4.
1,054
=
times
5.
0.96
=
6.
6 2 4 or 1 4
=
7.
= 211,076
equals
8.
21
=
9.
180
equals
10.
4,000
=
1,405
5 6 7 8 2 5 8 9
213,363
=
take away
7.
equals
of
8.
44
=
of
9.
240
equals
of
10.
4,200
=
Wednesday 1.
406,666
=
2.
299,200
=
101,110
3.
6
multiplied by
1,087
=
4.
1,098
=
times
5.
0.38
=
6.
9 4 5 or 1 5
7.
equals
8.
12
=
9.
90
equals
10.
2,400
=
6 7 2 5 3 7 6 9
2.
148,421
=
398,312
3.
7
multiplied by
1,543
=
10
4.
1,303
=
times
10
÷
100
5.
0.52
=
÷
100
add
5 5 2 14
6.
11 4 7 or 1 7
=
add
5 7 2 3
take away
14
=
of
9.
450
equals
of
10.
4,800
=
=
255,660
3.
7
multiplied by
1,607
=
4.
1,401
=
times
10
5.
0.22
=
÷
100
6.
10 3 7 or 1 7
=
add
5 7 1 3
=
9.
500
equals
10.
6,000
=
60
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 60
equals
8.
222,341
50
7.
of
2.
8.
of
more than less than
more than less than
5 6 5 6 5 9 6 7
of
=
552,892
equals
of
736,440
1.
7.
take away
1.
104,355
Friday =
6 8 4 5 3 4 6 8
337,647
Thursday more than less than
=
=
take away
335,561
7 9 2 6 5 6 6 7
617,202
take away
of of of
Ninja challenge
Sam has 700 groups of 90. How many does Sam have in total?
of of of Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 19 Monday 2.
10 12 20 21
3.
Tuesday equals
1.
minus
8 12 17 21
2.
11 12 19 21
equals
minus
9 12 11 21
=
0.43
x
100
equals
3.
0.63
x
100
equals
4.
8
subtract
1.45
=
4.
9
subtract
2.45
=
5.
6
–
4.2
=
5.
7
–
1.9
=
6.
270
shared by
6
=
6.
260
shared by
4
=
7.
6
x
159
=
7.
7
x
128
=
8.
96,381
+
56,381
=
8.
99,374
+
63,272
=
9.
105
÷
10
is equal to
9.
213
÷
10
is equal to
10.
42.5
divided by
10
=
10.
47.1
divided by
10
=
1. 2.
14 15 9 9
3.
1.
plus
Wednesday
plus
=
Thursday equals
1.
minus
12 15 1 9
=
2.
13 15 8 9
equals
minus
8 15 5 9
0.71
x
100
equals
3.
0.84
x
100
equals
4.
10
subtract
5.37
=
4.
11
subtract
4.52
=
5.
9
–
7.3
=
5.
8
–
5.3
=
6.
340
shared by
5
=
6.
380
shared by
5
=
7.
7
x
89
=
7.
7
x
65
=
8.
76,305
+
10,290
=
8.
81,283
+
12,289
=
9.
334
÷
10
is equal to
9.
513
÷
10
is equal to
10.
56.3
divided by
10
=
10.
61.2
divided by
10
=
plus
Friday 2.
3 15 8 10
equals
minus
14 15 7 10
3.
0.93
x
100
equals
4.
13
subtract
7.18
=
5.
7
–
4.9
=
6.
415
shared by
5
=
7.
7
x
77
=
8.
80,030
+
10,083
=
9.
627
÷
10
is equal to
10.
56.1
divided by
10
=
1.
plus
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 61
=
plus
=
Ninja challenge
Cho counts back 800 from 4,680. What number does Cho count back to?
61
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 19 Monday 1.
564,395
2.
Tuesday
+
40,000
=
=
564,395
+
1. 7,000
674,392
2.
+
3,000
=
=
674,392
+
3.
564,395
+
80
=
3.
674,392
+
90
=
4.
754
x
11
=
4.
533
x
11
=
5.
423
x
11
=
5.
493
x
11
=
6.
1 5 2 5 4 5 2 34
of
15
=
6.
of
42
=
of
15
=
7.
of
42
=
of
15
=
8.
of
42
=
+
5 8 2 14
1 6 4 6 5 6 4 13
+
5 6 4 13
=
7. 8. 9. 10.
=
9.
= +
5 8
10.
=
Wednesday 1.
284,593
2.
+
+
40,000
=
=
284,593
+
1. 50
193,493
2.
+
80,000
=
=
193,493
+
284,593
+
7,000
=
3.
193,493
+
800
=
4.
394
x
11
=
4.
586
x
11
=
5.
763
x
11
=
5.
643
x
11
=
6.
1 9 4 9 7 9 1 59
1 8 3 8 7 8 2 34
of
72
=
of
72
=
of
72
=
+
3 8 2 34
=
8. 9. 10.
of
36
=
6.
of
36
=
7.
of
36
=
8.
+
2 3 1 49
=
9.
= +
2 3
694,565
2.
+
800
=
=
694,565
+
3.
694,565
+
40,000
=
4.
938
x
11
=
5.
123
x
11
=
6.
1 9 4 9 7 9 3 5
of
63
=
of
63
=
of
63
=
+
2 1 15
=
7. 8. 9. 10.
=
3 5
62
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 62
+
10.
=
+
9,000
7 8
Ninja challenge
Friday 1.
1 6
Thursday
3.
7.
5,000
9,000
Tom shares 4,800 counters equally into 6 groups. How many counters will be in each group?
8 1 15 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 19 Monday 1.
Tuesday
=
350,371
+
98,273
1.
2.
=
377,101
–
87,063
3.
6
multiplied by
1,643
4.
1,554
÷
6
5.
10
–
6.
100
minus
17.4
7.
323,121
–
8. 9.
300,426
10.
=
272,361
+
45,381
2.
=
311,294
–
78,309
=
3.
3
multiplied by
1,729
=
=
4.
1,248
÷
4
=
5.
10
–
=
6.
100
minus
23.7
=
10,000
=
7.
101,353
–
10,000
=
=
450,342
+
=
299,102
+
–
100,000
=
–
100,000
=
=
210,034
+
=
100,264
+
10,000
=
8.24
1,000
8. 9.
10,000
481,283
10.
Wednesday
=
7.22
1,000
Thursday
1.
=
362,361
+
63,085
1.
=
417,114
+
91,173
2.
=
403,441
–
90,871
2.
=
516,391
–
98,388
3.
5
multiplied by
1,431
=
3.
8
multiplied by
1,652
=
4.
1,098
÷
3
=
4.
2,457
÷
7
=
5.
10
–
5.
10
–
6.
100
minus
39.6
=
6.
100
minus
56.2
=
7.
238,101
–
10,000
=
7.
198,281
–
10,000
=
=
301,283
+
=
412,361
+
–
100,000
=
–
100,000
=
=
275,371
+
=
312,331
+
8. 9.
714,332
10.
=
5.93
1,000
9. 10,000
Friday 1.
=
569,711
–
48,382
2.
=
201,110
–
87,277
3.
8
multiplied by
1,872
=
4.
2,611
÷
7
=
5.
10
–
6.
100
minus
62.6
=
7.
205,361
–
10,000
=
=
199,281
+
–
100,000
=
=
417,201
+
8. 9. 10.
172,361
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 63
8. 10.
804,203
=
3.19
1,000 10,000
Ninja challenge
Iko tells Sam that 240 is equal to 38 of 640. Is Iko correct? Explain why.
2.95
1,000 10,000 63
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 20 Monday
Tuesday
1.
0.17
multiplied by
100
equals
1.
0.56
multiplied by
100
equals
2.
403
÷
10
is equal to
2.
315
÷
10
is equal to
3.
56.1
divided by
10
=
3.
23.1
divided by
10
=
4.
5
÷
1,000
=
4.
7
÷
1,000
=
5.
0.56
x
1,000 equals
5.
0.67
x
1,000 equals
6.
26
shared by
100
=
6.
14
shared by
100
=
7.
4.6
times
1,000
=
7.
5.1
times
1,000
=
8.
125
÷
1,000
=
8.
203
÷
1,000
=
9.
7 15 9 11
plus
equals
9. 10.
minus
14 15 5 11
equals
=
6 15 6 11
plus
minus
13 15 6 11
1.
0.78
multiplied by
100
equals
1.
0.94
multiplied by
100
equals
2.
218
÷
10
is equal to
2.
305
÷
10
is equal to
3.
45.6
divided by
10
=
3.
50.1
divided by
10
=
4.
9
÷
1,000
=
4.
1
÷
1,000
=
5.
0.12
x
1,000 equals
5.
0.32
x
1,000 equals
6.
19
shared by
100
=
6.
26
shared by
100
=
7.
7.8
times
1,000
=
7.
4.6
times
1,000
=
8.
341
÷
1,000
=
8.
561
÷
1,000
=
9.
9 10 14 15
plus
equals
9. 10.
7 10 8 15
equals
=
8 10 12 15
plus
minus
9 10 11 15
1.
0.81
multiplied by
100
equals
2.
452
÷
10
is equal to
3.
62.2
divided by
10
=
4.
5
÷
1,000
=
5.
0.54
x
1,000 equals
6.
39
shared by
100
=
7.
5.1
times
1,000
=
8.
805
÷
1,000
=
9.
12 14 15 16
plus
7 14 8 16
equals
10.
Wednesday
10.
Thursday
Friday
10.
minus
64
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 64
=
minus
=
Ninja challenge
Sam has 4,700 marbles. Cho counts back 900 from 5,500 and states that she has more marbles than Sam. Is Cho correct? Explain why.
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 20 Monday 1.
Tuesday 1.
+
7,000
=
=
384,395
+
+
40,000
=
4.
=
345
x
11
5.
=
864
x
11
of
108
=
6.
of
108
=
7.
of
108
=
8.
+
1 49 2 3
384,395
2. 3.
6. 7. 8. 9.
384,395
1 9 5 9 8 9 2 3
10.
=
900
90,000
=
=
423,384
+
+
8,000
=
4.
=
392
x
11
5.
=
653
x
11
of
108
=
of
108
=
of
108
=
+
5 3 12 5 6
=
2. 3.
9.
= +
+
1 79
423,384 423,384
1 12 5 12 11 12 5 6
10.
=
Wednesday 1.
195,492
2. 3.
195,492
4. 5. 6. 7. 8. 9.
1 11 5 11 9 11 4 5
10.
1.
800
=
=
195,492
+
+
7,000
=
=
235
x
11
4.
=
865
x
11
5.
80,000
of
132
=
6.
of
132
=
7.
of
132
=
8.
+
3 1 25 4 5
9.
= +
9 1 25
80,000
=
=
274,291
+
+
7,000
=
4.
=
234
x
11
5.
=
394
x
11
of
90
=
of
90
=
of
90
=
+
5 14 2 47
=
2. 3.
6. 7. 8. 9. 10.
274,291
1 10 7 10 9 10 2 47
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 65
+
10.
393,391
1 11 5 11 9 11 3 8
+
60,000
=
=
393,391
+
+
8,000
=
=
342
x
11
=
643
x
11
of
99
=
of
99
=
of
99
=
+
3 1 16 6 8
=
=
+
70
3 1 16
Ninja challenge
+
274,291
393,391
2. 3.
Friday 1.
3 11 12
Thursday
+
=
+
80
80
Cho multiplies 512 by 5. Cho says her answer is greater than 2,500. Is Cho correct? Explain why.
9 14 65
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 20 Monday
Tuesday
1.
=
565,371
2.
=
204,281 minus
3.
=
1,253
multiplied by
9
4.
=
2093
÷
7
add
100,000
1.
=
412,271
1,000
2.
=
333,203 minus
3.
=
1,068
multiplied by
9
4.
=
2488
÷
8
add
5.
13
times
23
equals
5.
15
times
23
equals
6.
24
groups of
19
equals
6.
32
groups of
23
equals
7.
73,482
take away
100
=
7.
98,271
take away
100
=
=
102,173
+
=
232,277
+
–
10
=
–
10
=
8. 9.
231,112
10.
equals 512,183
+
10
8. 9.
100
145,361
10.
equals 104,372
Wednesday
+
100
add
100,000
1.
=
273,271
1,000
2.
=
173,869 minus
multiplied by
9
3.
=
1,642
multiplied by
9
2,808
÷
8
4.
=
3,160
÷
8
381,266
2.
=
204,371 minus
3.
=
1,174
4.
=
add
5.
25
times
28
equals
5.
27
times
34
equals
6.
31
groups of
42
equals
6.
33
groups of
45
equals
100
=
7.
100
=
=
663,778
+
=
473,271
+
–
10
=
–
10
=
8. 9.
255,331
10.
equals 176,445
+
10 100
1.
=
190,003
2.
=
103,038 minus
3.
=
1,771
multiplied by
9
4.
=
3,232
÷
8
add
5.
29
times
36
equals
6.
37
groups of
28
equals
100
=
=
503,271
+
–
10
=
111,173 take away
8. 9. 10.
333,277
equals 90,004
66
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 66
+
100,000
1,000
126,362 take away
8. 9.
Friday
7.
10
100,000
=
101,283 take away
1,000
Thursday
1.
7.
100,000
10.
641,263
equals 153,477
+
1,000
10 100
Ninja challenge
Iko says that the total of 90,384 minus 56,588 is 33,796. Is Iko correct? Explain why.
10 100 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 21 Monday
Tuesday
1.
0.93
x
100
=
1.
0.84
x
100
=
2.
105
÷
10
=
2.
111
÷
10
=
3.
13.9
÷
10
=
3.
45.1
÷
10
=
4.
14
÷
1,000
=
4.
23
÷
1,000
=
5.
0.54
x
100
=
5.
0.27
x
100
=
6.
71
÷
100
=
6.
83
÷
100
=
7.
6.1
x
1,000
=
7.
1.2
x
1,000
=
8.
732
÷
1,000
=
8.
106
÷
1,000
=
9.
15 16 19 20
+
15 16 15 20
=
9.
+
10.
12 16 10 20
=
=
11 16 16 20
10.
–
Wednesday
–
=
Thursday
1.
0.77
x
100
=
1.
0.63
x
100
=
2.
306
÷
10
=
2.
419
÷
10
=
3.
70.3
÷
10
=
3.
81.3
÷
10
=
4.
45
÷
1,000
=
4.
68
÷
1,000
=
5.
0.61
x
100
=
5.
0.82
x
100
=
6.
73
÷
100
=
6.
45
÷
100
=
7.
4.6
x
1,000
=
7.
1.9
x
1,000
=
8.
217
÷
1,000
=
8.
823
÷
1,000
=
9.
15 16 19 20
+
10 16 9 20
=
9.
+
10.
16 17 19 26
=
=
15 17 25 26
10.
–
Friday 1.
0.76
x
100
=
2.
608
÷
10
=
3.
91.4
÷
10
=
4.
91
÷
1,000
=
5.
0.67
x
100
=
6.
86
÷
100
=
7.
9.4
x
1,000
=
8.
184
÷
1,000
=
9.
16 19 21 26
+
16 19 19 26
=
10.
–
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 67
–
=
Ninja challenge
Sam counts back 1,000 from 6,360. Iko counts on 1,000 from 4,370. Who has more?
= 67
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 21 Monday 1.
263,293
2.
Tuesday
–
400
=
=
263,293
–
1. 90,000
235,247
2.
–
8,000
=
=
235,247
–
3.
263,293
–
8,000
=
3.
235,247
–
90
=
4.
345
x
3
=
4.
653
x
5
=
5.
345
x
9
=
5.
653
x
9
=
6.
345
x
93
=
6.
653
x
59
=
7.
4 9 4 9 1 14
2 3 2 3 4 12
of
240
=
of
2,400
=
–
5 8 4 12
=
8. 9. 10.
of
63
=
7.
of
630,000
=
8.
–
3 8 1 14
=
9.
= –
7 8
10.
=
Wednesday 1.
384,203
2.
–
–
5,000
=
=
384,203
–
1. 40
963,384
2.
–
500
=
=
963,384
–
384,203
–
800
=
3.
963,384
–
90,000
=
4.
247
x
7
=
4.
357
x
6
=
5.
247
x
3
=
5.
357
x
8
=
6.
247
x
37
=
6.
357
x
68
=
7.
2 5 2 5 1 23
of
350
=
7.
of
350
=
of
35,000
=
8.
of
350,000
=
–
5 6 1 23
3 7 3 7 2 34
–
5 8 2 34
=
9. 10.
=
9.
= –
1 6
124,242
2.
–
80,000
=
=
124,241
–
3.
124,241
–
500
=
4.
467
x
9
=
5.
467
x
3
=
6.
467
x
39
=
7.
5 8 5 8 2 58
of
480
=
of
48,000
=
–
3 4 2 58
=
8. 9. 10.
=
68
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 68
–
10.
=
–
8,000
7 8
Ninja challenge
Friday 1.
7 8
Thursday
3.
8.
70,000
7,000
Tom counts on 12 lots of 100 from 905. What number does Tom count on to?
1 4 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 21 Monday
Tuesday
1.
=
630
divided by
9
1.
=
560
divided by
8
2.
=
369
shared by
3
2.
=
972
shared by
4
3.
=
2,821
÷
7
3.
=
2,670
÷
6
9
4.
=
1,294
multiplied by
7
4.
=
1,032
multiplied by
5.
=
36
x
45
5.
=
44
x
37
6.
=
121
x
34
6.
=
132
x
24
x
5
7.
x
9
=
21,000
8.
=
49,000
=
6,000
9.
16,000
÷
=
4,000
10.
7,000
=
7.
20,000
8.
= x
9.
36,000
÷
10.
5,000
=
7 45,000
÷
27,000
= x
Wednesday
7 63,000
÷
Thursday
1.
=
630
divided by
7
1.
=
420
divided by
6
2.
=
880
shared by
5
2.
=
828
shared by
9
3.
=
1,990
÷
5
3.
=
1,888
÷
4
7
4.
=
2,136
multiplied by
6
4.
=
1,056
multiplied by
5.
=
46
x
32
5.
=
52
x
27
6.
=
109
x
33
6.
=
112
x
36
x
9
7.
x
5
=
30,000
8.
=
54,000
=
9,000
9.
15,000
÷
=
5,000
10.
3,000
=
7.
36,000
8.
= x
9.
72,000
÷
10.
12,000
=
6 84,000
÷
Friday 1.
=
450
divided by
5
2.
=
959
shared by
7
3.
=
3,624
÷
6 8
4.
=
1,980
multiplied by
5.
=
39
x
47
6.
=
126
x
41
x
4
=
18,000
=
12,000
7.
32,000
8.
= x
9.
36,000
÷
10.
12,000
=
6 96,000
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 69
35,000
= x
6 21,000
÷
Ninja challenge
Tom says that 175,495 is 90,005 more than 89,010. Is Tom correct? Explain why.
÷ 69
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 22 Monday
Tuesday
1.
0.76
x
10
=
1.
0.32
x
10
=
2.
413
÷
1,000
=
2.
562
÷
1,000
=
3.
23.6
÷
100
=
3.
13.3
÷
100
=
4.
52
÷
100
=
4.
54
÷
100
=
5.
0.33
x
1,000
=
5.
0.52
x
1,000
=
6.
76
÷
10
=
6.
94
÷
10
=
7.
5.9
x
10
=
7.
7.2
x
10
=
8.
129
÷
100
=
8.
304
÷
100
=
9.
10 12 19 25
+
14 12 10 25
=
9.
+
10.
9 12 10 25
=
=
9 12 15 25
10.
–
Wednesday
–
=
Thursday
1.
0.56
x
10
=
1.
0.85
x
10
=
2.
284
÷
1,000
=
2.
363
÷
1,000
=
3.
15.2
÷
100
=
3.
17.9
÷
100
=
4.
51
÷
100
=
4.
63
÷
100
=
5.
0.59
x
1,000
=
5.
0.29
x
1,000
=
6.
25
÷
10
=
6.
52
÷
10
=
7.
6.9
x
10
=
7.
8.1
x
10
=
8.
283
÷
100
=
8.
271
÷
100
=
9.
5 12 19 25
+
10 12 11 25
=
9.
+
10.
10 16 13 30
=
=
9 16 27 30
10.
–
Friday 1.
0.93
x
10
=
2.
415
÷
1,000
=
3.
23.5
÷
100
=
4.
43
÷
100
=
5.
0.67
x
1,000
=
6.
83
÷
10
=
7.
4.5
x
10
=
8.
831
÷
100
=
9.
12 16 29 30
+
8 16 16 30
=
10.
–
70
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 70
–
=
Ninja challenge
Tom counts back 1,000 from 4,390. Cho counts on 1,000 from 2,290. Who has more?
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 22 Monday 1.
326,584
2.
Tuesday
–
8,000
=
=
326,584
–
1. 40,000
420,134
2.
–
7,000
=
=
420,134
–
3.
326,584
–
900
=
3.
420,134
–
50,000
=
4.
875
x
4
=
4.
865
x
5
=
5.
875
x
5
=
5.
865
x
9
=
6.
875
x
54
=
6.
865
x
95
=
7.
7 9 7 9 2 215
4 5 4 5 2 19
of
450
=
of
45,000
=
–
1 3 2 59
=
8. 9. 10.
of
630
=
7.
of
6,300
=
8.
–
3 5 2 215
=
9.
= –
4 5
10.
=
Wednesday 1.
925,023
2.
400
=
=
925,023
–
x
8
=
7
=
5.
764
x
5
=
x
73
=
6.
764
x
58
=
of
420
=
7.
of
400
=
of
42,000
=
8.
of
4,000
=
–
4 5 7 210
2 5 2 5 3 49
–
2 3 3 79
=
463
x
6.
463
7.
4 7 4 7 9 210
=
9.
= –
4 5
–
80,000
=
=
910,192
–
3.
910,192
–
500
=
4.
712
x
8
=
5.
712
x
3
=
6.
712
x
38
=
7.
2 11 2 11 2 59
of
990
=
of
9,900
=
–
2 3 2 79
=
10.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 71
–
10.
=
7,000
–
2 3
Ninja challenge
Friday
9.
–
764
5.
8.
802,149
4.
3
2.
=
=
x
910,192
= =
463
1.
30,000 600
4.
10.
2.
– –
70,000
9.
7,000
802,149 802,149
–
8.
1. 3.
925,023
1 3
–
Thursday
–
3.
800
6,000
Sam divides 7,200 by 8. Sam states that his answer is greater than 800 and less than 1,000. Is Sam correct? Explain why.
2 3 71
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 22 Monday
Tuesday
1.
90
=
divided by
4
1.
80
=
divided by
6
2.
141
equals
shared by
7
2.
137
equals
shared by
7
3.
651
=
÷
6
3.
458
=
÷
9
4.
is equal to
1,734
multiplied by
9
4.
is equal to
2,073
multiplied by
9
5.
=
45
times
27
5.
=
48
times
34
6.
equals
426
groups of
41
6.
equals
326
groups of
38
times
4
7.
times
6
=
27,000
8.
22,000
7.
36,000
8. 9. 10.
= x
4 5 2 10
9
x
2
=
9.
x
4
=
10.
24,000 6 9 2 15
Wednesday
= x
2
=
x
2
=
x
6
=
Thursday
1.
90
=
divided by
4
1.
30
=
divided by
9
2.
97
equals
shared by
9
2.
153
equals
shared by
6
3.
471
=
÷
9
3.
393
=
÷
7
4.
is equal to
2,067
multiplied by
7
4.
is equal to
3,103
multiplied by
4
5.
=
52
times
37
5.
=
55
times
36
6.
equals
263
groups of
45
6.
equals
293
groups of
48
times
6
7.
times
4
=
28,000
8.
48,000
7.
42,000
8. 9. 10.
= x
7 12 4 15
4
x
2
=
9.
x
3
=
10.
Friday 1.
70
=
divided by
12
2.
159
equals
shared by
6
3.
412
=
÷
8
4.
is equal to
4,212
multiplied by
5
5.
=
56
times
27
6.
equals
175
groups of
62
times
6 56,000
7.
30,000
8. 9. 10.
2 14 3 11
= x
8
=
x
9
=
x
3
=
72
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 72
32,000 9 12 2 9
= x
8
=
x
2
=
x
3
=
Ninja challenge
What number does Sam multiply 6,000 by to get an answer of 54,000?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 23 Monday
Tuesday
1.
180,000
–
90,000
=
1.
230,000
–
120,000
=
2.
240,000
+
70,000
=
2.
150,000
+
90,000
=
3.
100
–
76
=
3.
100
–
45
=
4.
1
–
0.76
=
4.
1
–
0.45
=
5.
10
–
7.6
=
5.
10
–
4.5
=
6.
0.45
x
100
=
6.
0.74
x
100
=
7.
703
÷
100
=
7.
627
÷
100
=
8.
1 2
+
1 3
=
8.
1 3
+
1 4
=
9.
4
x
56
=
9.
5
x
73
=
10.
456
÷
6
=
10.
588
÷
7
=
Wednesday
Thursday
1.
340,000
–
290,000
=
1.
440,000
–
190,000
=
2.
170,000
+
80,000
=
2.
190,000
+
180,000
=
3.
100
–
67
=
3.
100
–
12
=
4.
1
–
0.67
=
4.
1
–
0.12
=
5.
10
–
6.7
=
5.
10
–
1.2
=
6.
0.83
x
100
=
6.
0.79
x
100
=
7.
326
÷
100
=
7.
164
÷
100
=
8.
1 5
+
1 10
=
8.
1 3
+
1 6
=
9.
6
x
154
=
9.
4
x
673
=
10.
588
÷
6
=
10.
618
÷
6
=
Friday 1.
390,000
–
170,000
=
2.
210,000
+
190,000
=
3.
100
–
37
=
4.
1
–
0.37
=
5.
10
–
3.7
=
6.
0.49
x
100
=
7.
504
÷
100
=
8.
1 4
+
1 8
=
9.
7
x
406
=
10.
605
÷
5
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 73
Ninja challenge
Sam adds 1,000 to 4,500. Tom subtracts 1,500 from 7,000. Iko adds 500 to 5,500. Who has more?
73
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 23 Monday 1.
848,294
2.
Tuesday
+
7,000
=
=
848,294
–
1. 500
384,794
2.
–
8,000
=
=
384,794
+
3.
848,294
–
70,000
=
3.
384,794
–
90,000
=
4.
264
x
73
=
4.
765
x
23
=
5.
264
x
37
=
5.
765
x
32
=
6.
2,448
÷
6
=
6.
1,504
÷
8
=
7.
1 6 5 6 1 59
1 8 5 8 1 510
of
5,600
=
of
5,600
=
+
3 5 1 510
=
8. 9. 10.
of
2,400
=
7.
of
2,400
=
8.
+
2 3 1 79
=
9.
= –
2 3
10.
=
Wednesday 1.
694,024
2.
–
+
80,000
=
=
694,024
–
1. 700
208,384
2.
–
70,000
=
=
208,384
+
694,024
–
8,000
=
3.
208,384
–
600
=
4.
853
x
56
=
4.
294
x
85
=
5.
853
x
65
=
5.
294
x
58
=
6.
1,460
÷
4
=
6.
2,002
÷
7
=
7.
1 4 3 4 2 47
of
4,800
=
7.
of
4,200
=
of
4,800
=
8.
of
4,200
=
+
5 14 2 17
1 7 3 7 4 13
–
5 6 4 23
=
9. 10.
=
9.
= –
5 14
283,291
2.
+
70,000
=
=
283,291
–
3.
283,291
–
600
=
4.
562
x
38
=
5.
562
x
83
=
6.
1,116
÷
9
=
7.
1 9 4 9 7 120
of
1,800
=
of
1,800
=
+
4 5 3 120
=
8. 9. 10.
=
74
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 74
–
10.
=
+
9,000
5 6
Ninja challenge
Friday 1.
3 5
Thursday
3.
8.
700
6,000
Sam subtracts 900 from 197,371. What answer does Sam get?
3 5 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 23 Monday
Tuesday
1.
=
42
÷
6
1.
=
56
÷
7
2.
=
704
÷
4
2.
=
915
÷
5
3.
=
2,660
÷
5
3.
=
4,368
÷
8
4.
=
3,132
x
4
4.
=
3,054
x
4
5.
=
35
x
29
5.
=
38
x
43
6.
=
213
x
43
6.
=
213
x
43
=
3 7 3 4
+
2 14
=
+
2 8
=
–
3 4 3 6
=
x
4
=
9.
x
5
=
x
6
=
10.
x
8
=
7. 8. 9. 10.
1 45 2 5 2 14
–
7. 8.
1 23 2 6 2 20
Wednesday
Thursday
1.
=
72
÷
8
1.
=
54
÷
6
2.
=
970
÷
5
2.
=
1,827
÷
9
3.
=
3,892
÷
7
3.
=
1,836
÷
3
4.
=
4,501
x
4
4.
=
3,075
x
5
5.
=
46
x
41
5.
=
49
x
37
6.
=
194
x
52
6.
=
136
x
62
7.
=
2 5 5 8
+
8 10
7.
=
+
7 9
=
–
1 3 9 10
=
x
5
=
9.
x
4
=
x
2
=
10.
x
3
=
8. 9. 10.
1 14 5 8 3 12
–
8.
Friday 1.
=
108
÷
9
2.
=
762
÷
3
3.
=
3,846
÷
6
4.
=
2,613
x
7
5.
=
48
x
62
6.
=
179
x
58
=
+
4 5
–
2 3 9 12
=
x
2
=
x
4
=
7. 8. 9. 10.
1 34 5 9 3 15
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 75
1 15 5 7 3 13
Ninja challenge
Sam multiplies the product of 70 times 9 by 8. What answer does Sam have?
75
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 24 Monday
Tuesday
1.
60,560
–
14,000
=
1.
50,360
–
13,000
=
2.
40,670
+
27,000
=
2.
41,270
+
19,000
=
3.
100
–
69
=
3.
100
–
41
=
4.
1
–
0.69
=
4.
1
–
0.41
=
5.
0.47
x
10
=
5.
0.67
x
10
=
6.
1,504
÷
1,000
=
6.
2,364
÷
1,000
=
7.
+
7. 8.
+
1 9 1 6
=
=
1 3 1 2
+
+
1 10 1 4
=
8.
1 5 1 2
9.
5
x
152
=
9.
5
x
242
=
10.
770
÷
5
=
10.
895
÷
5
=
Wednesday
=
Thursday
1.
80,370
–
23,000
=
1.
73,280
–
45,000
=
2.
28,370
+
21,000
=
2.
35,170
+
29,000
=
3.
100
–
76
=
3.
100
–
99
=
4.
1
–
0.76
=
4.
1
–
0.99
=
5.
0.78
x
10
=
5.
0.02
x
10
=
6.
2,006
÷
1,000
=
6.
4,739
÷
1,000
=
7.
+
7. 8.
+
1 15 1 12
=
=
1 5 1 3
+
+
1 12 1 9
=
8.
1 4 1 3
9.
5
x
364
=
9.
5
x
451
=
10.
1,225
÷
5
=
10.
1,865
÷
5
=
Friday 1.
79,270
–
21,000
=
2.
45,370
+
14,000
=
3.
100
–
1
=
4.
1
–
0.01
=
5.
0.13
x
10
=
6.
6,046
÷
1,000
=
7.
+ +
1 20 1 20
=
8.
1 10 1 5
9.
5
x
489
=
10.
1,990
÷
5
=
76
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 76
=
Ninja challenge
Tom says half of 1,000 is greater than a quarter of 2,000. Is Tom correct? Explain why.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 24 Monday 1.
291,395
2.
Tuesday
+
50,000
=
=
291,395
–
1. 4,000
916,094
2.
–
60,000
=
=
916,094
–
3.
291,395
–
800
=
3.
916,094
+
8,000
=
4.
964
x
48
=
4.
172
x
59
=
5.
964
x
84
=
5.
172
x
95
=
6.
1,752
÷
3
=
6.
1,950
÷
6
=
7.
1 3 2 3 4 215
1 6 5 6 2 58
of
42,000
=
of
42,000
=
+
1 4 2 78
=
8. 9. 10.
of
1,800
=
7.
of
1,800
=
8.
+
3 5 7 215
=
9.
= –
3 5
10.
=
Wednesday 1.
904,803
2.
–
+
700
=
=
904,803
–
1. 30,000
395,037
2.
+
80,000
=
=
395,037
–
904,803
–
7,000
=
3.
395,037
–
400
=
4.
394
x
27
=
4.
753
x
74
=
5.
394
x
72
=
5.
753
x
47
=
6.
3,270
÷
5
=
6.
2,608
÷
8
=
7.
1 5 4 5 5 212
of
600,000
=
7.
of
560,000
=
of
600,000
=
8.
of
560,000
=
+
5 6 1 212
1 8 7 8 2 35
+
7 10 2 15
=
9. 10.
=
9.
= –
5 6
309,827
2.
+
8,000
=
309,827
–
3.
309,827
+
600
=
4.
172
x
37
=
5.
172
x
73
=
6.
1,278
÷
9
=
7.
1 9 7 9 7 112
of
2,700
=
of
2,700
=
+
3 4 5 112
=
8. 9. 10.
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 77
10.
=
–
8,000
7 10
Ninja challenge
Friday 1.
1 4
Thursday
3.
8.
800
–
50,000
Cho explained how 8 groups of 5,000 is equal to 4,000 groups of 10. Is Cho correct? Explain why.
3 4 77
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 24 Monday
Tuesday
1.
17
–
1.
19
–
2.
4
=
2.
1.4
=
3.
317
=
÷
4
3.
219
=
÷
5
4.
504
=
÷
6
4.
174
=
÷
8
= 0.04
7.55
x
= 0.14
7.61
x
5.
=
1,830
x
5
5.
=
937
x
8
6.
=
205
x
43
6.
=
304
x
17
=
2 3 6 8
–
1 5
=
–
3 10
=
–
4 5 7 8
=
x
3
=
9.
x
2
=
x
3
=
10.
x
5
=
7. 8. 9. 10.
1 14 5 10 3 9
–
7. 8.
2 14 9 12 3 10
Wednesday
Thursday
1.
22
–
1.
19
–
2.
56
=
2.
11.3
=
3.
352
=
÷
7
3.
284
=
÷
9
4.
208
=
÷
9
4.
519
=
÷
3
= 0.56
7.73
x
= 1.13
12.93
x
5.
=
617
x
6
5.
=
718
x
5
6.
=
412
x
29
6.
=
377
x
35
7.
=
3 5 5 9
–
4 10
7.
=
–
4 5
=
–
9 10 5 10
=
x
2
=
9.
x
3
=
x
5
=
10.
x
6
=
8. 9. 10.
2 13 9 17 3 4
–
8.
Friday 1.
27
–
2.
204
=
3.
311
=
÷
7
4.
621
=
÷
6
= 2.04
7.55
x
5.
=
815
x
2
6.
=
184
x
42
=
–
1 3
–
9 12 5 6
=
x
2
=
x
7
=
7. 8. 9. 10.
3 12 9 12 3 7
78
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 78
2 15 9 10 3 5
Ninja challenge
Cho has a total of 54,000. If Cho has 9 equal groups, what is each equal group made up of?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 25 Monday
Tuesday
1.
81,270
–
19,038
=
1.
67,380
–
21,036
=
2.
21,270
+
17,037
=
2.
35,390
+
14,037
=
3.
0.13
x
1,000
=
3.
0.65
x
1,000
=
4.
646
÷
1,000
=
4.
153
÷
1,000
=
5.
1,000
334,312
=
5.
1,000
=
1,000
126,390
=
6.
1,000
192,374
=
7.
+
1 9 1 15
=
8.
1 2 1 5
more than less than
216,373
6.
more than less than
9. 10.
=
7.
+
1 10 1 10
=
8.
1 3 1 3
6
x
95
=
9.
6
x
93
=
498
÷
6
=
10.
438
÷
6
=
+
Wednesday
+
=
Thursday
1.
69,370
–
45,056
=
1.
71,270
–
28,082
=
2.
45,340
+
19,031
=
2.
56,047
+
21,205
=
3.
0.83
x
1,000
=
3.
0.71
x
1,000
=
4.
364
÷
1,000
=
4.
637
÷
1,000
=
5.
1,000
=
1,000
278,005
=
7.
+
1 18 1 22
=
8.
1 7 1 8
more than less than
101,374
6.
more than less than
9. 10.
129,380
=
5.
1,000
306,305
=
6.
1,000
=
7.
+
1 14 1 16
=
8.
1 9 1 11
6
x
105
=
9.
6
x
243
=
594
÷
6
=
10.
654
÷
6
=
+
Friday 1.
65,506
–
29,046
=
2.
50,040
+
28,055
=
3.
0.59
x
1,000
=
4.
183
÷
1,000
=
5.
1,000
199,293
=
6.
1,000
100,304
=
7.
+
1 5 1 6
=
8.
1 4 1 4
more than less than
9.
6
x
187
=
10.
924
÷
6
=
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 79
+
=
Ninja challenge
Tom totals 9 groups of 30. Sam totals 7 groups of 40. Sam says that his total is greater than Tom’s. Is Sam correct? Explain why.
=
79
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 25 Monday 1.
485,294
2.
Tuesday
+
50,000
=
=
485,294
–
1. 700
920,394
2.
–
7,000
=
=
920,394
+
3.
485,294
–
8,000
=
3.
920,394
–
700
=
4.
261
x
59
=
4.
372
x
57
=
5.
261
x
95
=
5.
372
x
75
=
6.
4,144
÷
7
=
6.
3,416
÷
4
=
7.
1 7 5 7 4 56
1 4 3 4 5 12
of
3,600
=
of
3,600
=
+
7 10 5 12
=
8. 9. 10.
of
63,000
=
7.
of
63,000
=
8.
+
2 3 3 56
=
9.
= –
2 3
10.
=
Wednesday 1.
294,213
2.
–
+
70,000
=
=
294,213
–
1. 8,000
938,293
2.
–
80,000
=
=
938,293
+
294,213
–
700
=
3.
938,293
–
600
=
4.
294
x
28
=
4.
173
x
84
=
5.
294
x
82
=
5.
173
x
48
=
6.
2,304
÷
9
=
6.
4,710
÷
6
=
7.
1 9 4 9 111 12
of
63,000
=
7.
of
120,000
=
of
63,000
=
8.
of
120,000
=
+
5 6 5 112
1 6 4 6 113 14
–
3 7 5 114
=
9. 10.
=
9.
= –
5 6
284,028
2.
+
60,000
=
=
284,028
–
3.
284,028
–
700
=
4.
184
x
82
=
5.
184
x
28
=
6.
2,947
÷
7
=
7.
1 7 5 7 213 15
of
35,000
=
of
35,000
=
+
4 5 7 215
=
8. 9. 10.
=
80
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 80
–
10.
=
–
5,000
3 7
Ninja challenge
Friday 1.
3 10
Thursday
3.
8.
90
7,000
Cho says that the difference between 57,684 and 49,576 is 8,801. Is Cho correct? Explain why.
4 5 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 25 Monday 1.
10
–
2.
260
=
3.
203
=
609
4.
511
=
2,555
5.
2,852
=
6.
10,962
=
7. 8. 9. 10.
3.05
2 6 5 6
1.
40
–
2.
145
=
÷
3.
211
=
1,266
÷
÷
4.
832
=
4,160
÷
= x
1,000
x
4
5.
2,996
=
x
27
6.
13,860
=
–
2 4
8 12 5 6
=
x
5
=
9.
x
5
=
10.
= 3 13
Tuesday
–
7. 8.
4 8 2 6
Wednesday 60
–
2.
30
=
3.
307
=
2,456
4.
572
=
5,148
5.
3,834
=
x
6.
19,710
=
7. 8. 9. 10.
1 19 3 9 5 7
=
x
5
=
÷
÷
4.
563
=
4,504
÷
6
5.
3,682
=
x
7
x
45
6.
35,360
=
x
65
–
12 16
7.
–
10 14
=
9.
x
5
=
10.
=
3.
602
=
2,408
÷
4.
598
=
5,382
÷
5.
2,946
=
6.
41,038
=
8.
x
1,000
x
6
x
71
–
10 18
–
=
x
5
=
x
4
=
6 9 3 7
= x
–
6 7 2 3
=
x
4
=
x
6
=
= 1 15
38.79
1,000
Ninja challenge
=
5 6 2 3
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 81
5
2,838
5
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
x
=
1,060
10.
=
473
2.
6 10 3 5
–
3.
–
9.
3 4
÷
80
1 24
–
=
1.
8.
36
170
x
=
x
2.
1,000
Friday
7.
7
–
=
41.74
x
70
7 8 2 3
–
100
1.
= x
=
x
Thursday
1.
42.09
=
7 8 9 10
= 4 15
13.21
Cho says that 90,989 less than 198,899 equals 108,011. Is Cho correct? Explain why.
81
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 26 Monday
Tuesday
1.
65,506 minus
1,000
1.
17,382 minus
1,000
2.
50,040
plus
1,000 equals
3.
100
198,283
=
4.
100
more than less than
2.
23,703
plus
1,000 equals
3.
100
204,043
=
=
4.
100
more than less than
114,355
190,392
=
5.
half
of
240
equals
5.
half
of
180
equals
6.
double
7. 8.
1 6 1 5
of
140
=
6.
double
of
210
=
+
=
7. 8.
+
1 18 1 6
=
equals
1 9 1 3
+
+
1 18 1 6
equals
9.
7
x
78
=
9.
7
x
89
=
10.
623
÷
7
=
10.
735
÷
7
=
=
Wednesday
=
Thursday
1.
43,284 minus
1,000
1.
20,290 minus
1,000
2.
20,322
plus
1,000 equals
2.
19,008
plus
1,000 equals
3.
100
330,047
4.
100
more than less than
=
3.
100
700,304
=
160,037
=
4.
100
more than less than
101,101
=
5.
half
of
420
equals
5.
half
of
860
equals
6.
double
of
350
=
6.
double
of
460
=
7.
+
7. 8.
+
1 18 1 6
=
equals
1 6 1 4
+
+
1 18 1 6
=
8.
1 3 1 2
equals
9.
7
x
93
=
9.
7
x
141
=
10.
875
÷
7
=
10.
910
÷
7
=
=
Friday 1.
45,302 minus
1,000
2.
32,290
plus
1,000 equals
3.
100
560,361
=
4.
100
more than less than
202,203
=
5.
half
of
820
equals
6.
double
of
510
=
7.
+ +
1 18 1 5
=
8.
1 9 1 4
equals
9.
7
x
153
=
10.
1,141
÷
7
=
82
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 82
=
=
Ninja challenge
Cho counts on 10,000 from 1,004. What number does Cho count on to?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 26 Monday
Tuesday
1.
4.6
+
2.7
=
1.
2.5
+
9.8
=
2.
14.6
+
32.7
=
2.
2.53
+
9.82
=
3.
14.65
+
32.73
=
3.
32.53
+
9.82
=
4.
1,410
÷
6
=
4.
2,748
÷
6
=
5.
1,410
÷
3
=
5.
2,748
÷
3
=
6.
4x
35
=
4x5x
6.
4x
40
=
10 x 2 x
7.
2 x 35 x
2
=
10 x 7 x
7.
4x5x
8
=
2 x 40 x
8.
1 8 1 8 1 8
1 7 1 7 1 7
x
3
=
x
2
=
9. 10.
x
5
=
8.
x
7
=
9.
x
=
3 8
10.
Wednesday
x
=
Thursday
1.
9.6
+
2.7
=
1.
5.8
+
2.9
=
2.
9.62
+
2.74
=
2.
35.8
+
12.9
=
3.
59.62
+
12.74
=
3.
35.82
+
12.94
=
4.
1,716
÷
6
=
4.
2,848
÷
8
=
5.
1,716
÷
3
=
5.
2,848
÷
4
=
6.
9 x 10 x
4
=
20 x 3 x
6.
6x4x
10
=
10 x 12 x
7.
18 x 2 x
10
=
3x2x
7.
60 x 2 x
2
=
10 x 3 x
8.
1 12 1 12 1 12
x
7
=
8.
x
3
=
x
5
=
1 12 1 12 1 12
x
6
=
9. 10.
x
=
9. 11 12
1.
2.4
+
5.8
=
2.
2.43
+
5.85
=
3.
22.43
+
15.85
=
4.
2,032
÷
8
=
5.
2,032
÷
4
=
6.
7x4x
10
=
7x2x
7.
2 x 10 x
14
=
2x7x
8.
1 16 1 16 1 16
x
11
=
x
15
=
10.
x
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 83
=
10.
x
=
9 3 12 or 4
Ninja challenge
Friday
9.
5 7
Sam shares 9,600 into 4 equal groups. How much will Sam have in each group?
5 16 83
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 26 Monday
Tuesday
1.
10%
of
400
=
1.
10%
of
4,000
=
2.
10%
of
300
=
2.
10%
of
5,000
=
3.
10%
of
700
=
3.
10%
of
9,000
=
4.
10%
of
800
=
4.
10%
of
200
=
5.
10%
of
340
=
5.
10%
of
600
=
6.
10%
of
560
=
6.
10%
of
510
=
7.
10%
of
730
=
7.
10%
of
960
=
8.
10%
of
76
=
8.
10%
of
23
=
9.
10%
of
45
=
9.
10%
of
62
=
10.
10%
of
92
=
10.
10%
of
174
=
Wednesday
Thursday
1.
10%
of
7,000
=
1.
10%
of
7,500
=
2.
10%
of
3,000
=
2.
10%
of
1,400
=
3.
10%
of
800
=
3.
10%
of
820
=
4.
10%
of
100
=
4.
10%
of
190
=
5.
10%
of
670
=
5.
10%
of
675
=
6.
10%
of
290
=
6.
10%
of
291
=
7.
10%
of
79
=
7.
10%
of
83
=
8.
10%
of
13
=
8.
10%
of
26
=
9.
10%
of
267
=
9.
10%
of
109
=
10.
10%
of
671
=
10.
10%
of
502
=
Friday 1.
10%
of
6,700
=
2.
10%
of
2,600
=
3.
10%
of
910
=
4.
10%
of
450
=
5.
10%
of
195
=
6.
10%
of
367
=
7.
10%
of
142
=
8.
10%
of
7
=
9.
10%
of
14
=
10.
10%
of
2
=
84
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 84
Ninja challenge
Cho adds an unknown number to 417,500 and gets an answer of 713,290. What is Cho’s unknown number?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 27 Monday
Tuesday
1.
4
x
9
=
1.
8
x
9
=
2.
4
x
90
=
2.
8
x
90
=
3.
6
x
7
=
3.
5
x
7
=
4.
6
x
70
=
4.
5
x
70
=
5.
of
50
=
5.
24
=
of
500
=
6.
of
240
=
+
=
7.
+
equals
8.
+
1 12 1 10
=
+
1 8 1 8
3 8 3 8 1 3 1 5
of
8.
3 5 3 5 1 2 1 6
equals
9.
8
x
36
=
9.
8
x
44
=
10.
448
÷
8
=
10.
440
÷
8
=
6. 7.
Wednesday
Thursday
1.
8
x
8
=
1.
6
x
6
=
2.
8
x
80
=
2.
6
x
60
=
3.
12
x
9
=
3.
7
x
7
=
4.
12
x
90
=
4.
7
x
70
=
5.
of
35
=
5.
36
=
of
350
=
6.
of
360
=
+
=
7.
+
equals
8.
+
1 12 1 14
=
+
1 12 1 15
4 9 4 9 1 3 1 7
of
8.
4 7 4 7 1 4 1 5
equals
9.
8
x
62
=
9.
8
x
74
=
10.
576
÷
8
=
10.
656
÷
8
=
6. 7.
Friday 1.
8
x
6
=
2.
8
x
60
=
3.
9
x
7
=
4.
9
x
70
=
5.
of
42
=
of
420
=
+ +
1 12 1 15
=
8.
6 7 6 7 1 6 1 3
equals
9.
8
x
89
=
10.
824
÷
8
=
6. 7.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 85
Ninja challenge
Cho counts back 1,000 from 10,002. What number does Cho count back to?
85
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 27 Monday
Tuesday
1.
6.4
+
3.9
=
1.
6.7
+
4.6
=
2.
6.46
+
3.95
=
2.
6.78
+
4.65
=
3.
26.46
+
13.95
=
3.
36.78
+
24.65
=
4.
1,625
÷
5
=
4.
2,268
÷
6
=
5.
1,645
÷
5
=
5.
2,292
÷
6
=
6.
5x5x
10
=
5x
6.
12 x
10
=
3 x 10 x
7.
5x2x
25
=
25 x
7.
6x
20
=
6x4x
8.
1 20 1 20 1 20
1 24 1 24 1 24
x
17
=
x
19
=
9. 10.
x
17
=
8.
x
11
=
9.
x
=
13 20
10.
Wednesday
x
=
Thursday
1.
9.6
+
3.9
=
1.
7.5
+
3.6
=
2.
9.67
+
3.98
=
2.
7.58
+
3.67
=
3.
19.67
+
33.98
=
3.
27.58
+
43.67
=
4.
3,801
÷
7
=
4.
680
÷
8
=
5.
3,864
÷
7
=
5.
776
÷
8
=
6.
48 x
10
=
12 x 10 x
6.
27 x
10
=
3 x 30 x
7.
6x
80
=
8x
7.
9x3x
10
=
30 x
8.
1 19 1 19 1 19
x
13
=
8.
x
15
=
x
14
=
1 27 1 27 1 27
x
13
=
9. 10.
x
=
9. 17 19
1.
3.8
+
5.7
=
2.
43.8
+
25.7
=
3.
43.87
+
25.76
=
4.
1,134
÷
9
=
5.
1,188
÷
9
=
6.
30 x
10
=
5 x 10 x
7.
30 x 5 x
2
=
20 x 5 x
8.
1 27 1 27 1 27
x
11
=
x
26
=
10.
x
86
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 86
=
10.
x
=
23 27
Ninja challenge
Friday
9.
7 24
Sam says that 20.5 minus 14.4 is equal to 7.3. Is Sam correct? Explain why.
25 27 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 27 Monday 1.
10%
of
2.
10%
of
3.
10%
of
4.
10%
of
5.
10%
of
6.
10%
of
7.
10%
of
8.
10%
of
9.
10%
of
10.
10%
of
1,300
Tuesday = =
710
= =
107
27.8
= =
61
62
= =
628
490
0.3
= =
0.02
1.
10%
of
2.
10%
of
3.
10%
of
4.
10%
of
5.
10%
of
6.
10%
of
7.
10%
of
8.
10%
of
9.
10%
of
10.
10%
of
Wednesday 1.
10%
of
2.
10%
of
3.
10%
of
4.
10%
of
5.
10%
of
6.
10%
of
7.
10%
of
8.
10%
of
9.
10%
of
10.
10%
of
230,000
=
531
= =
124
1,215
= =
1,210
45,700
= =
15,340
14.3
= =
0.6
10%
of
2.
10%
of
3.
10%
of
4.
10%
of
5.
10%
of
6.
10%
of
7.
10%
of
8.
10%
of
9.
10%
of
10.
10%
of
562,000
= =
843,000
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 87
= =
5,490
= =
219
31.5
= =
93
234
0.03
= =
0.05
1.
10%
of
2.
10%
of
3.
10%
of
4.
10%
of
5.
10%
of
6.
10%
of
7.
10%
of
8.
10%
of
9.
10%
of
10.
10%
of
471,000
= =
614,000
= =
13,250
478
= =
459
1,847
= =
2,540
94,300
36.5
= =
0.66
2,385
The answer to the question is 50. To get to the answer, Sam halved a number, then divided it by 40 and then added 45. What number did Sam start with?
731
= =
604
1,840
3,630
= =
6,430
71,300
= =
45,390
=
Ninja challenge
Friday 1.
=
Thursday =
251,000
41,700
19.7
= =
0.75 87
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 28 Monday
Tuesday
1.
13
x
14
=
1.
13
x
15
=
2.
12
x
23
=
2.
14
x
16
=
3.
x
3
=
x
4
=
+
4 5
=
of
160
=
+ +
1 8 1 9
=
8.
1 4 1 5 1 25 2 5 2 3 2 3
equals
9. 10.
4. 5. 6. 7.
x
3
=
3.
x
4
=
4.
+
4 5
=
5.
of
250
=
6.
+
=
7.
+
1 9 1 6
equals
8.
1 6 1 7 1 45 2 8 2 4 2 3
9
x
54
=
9.
9
x
61
=
603
÷
9
=
10.
738
÷
9
=
Wednesday
Thursday
1.
14
x
17
=
1.
13
x
21
=
2.
12
x
16
=
2.
22
x
14
=
3.
x
3
=
3.
7
=
x
6
=
4.
x
8
=
+
5 6
=
5.
+
2 3
=
of
180
=
6.
of
360
=
+
=
7.
+
equals
8.
+
2 12 2 12
=
+
1 10 1 12
1 12 1 10 2 23 4 6 2 6 2 3
x
8.
1 8 1 9 2 46 4 9 2 5 2 3
equals
9.
9
x
67
=
9.
9
x
71
=
10.
783
÷
9
=
10.
819
÷
9
=
4. 5. 6. 7.
Friday 1.
15
x
22
=
2.
23
x
13
=
3.
x
5
=
x
3
=
+
5 7
=
of
480
=
+ +
2 15 2 6
=
8.
1 8 1 7 1 57 5 8 2 5 1 3
equals
9.
9
x
88
=
10.
891
÷
9
=
4. 5. 6. 7.
88
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 88
Ninja challenge
Tom totals 9 groups of 40. Sam totals 6 groups of 60. Sam says that his total is greater than Tom’s. Is Sam correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 28 Monday
Tuesday
1.
7.3
–
3.9
=
1.
8.4
–
2.8
=
2.
7.35
–
3.98
=
2.
48.4
–
12.8
=
3.
17.35
–
3.98
=
3.
48.46
–
12.87
=
4.
235
÷
2
=
4.
967
÷
2
=
5.
257
÷
2
=
5.
975
÷
2
=
6.
3x
270
=
3x3x9x
6.
4x
240
=
4x6x
7.
3x3x
90
=
90 x
7.
4 x 60 x
4
=
8x6x
8.
2 8 3 8 3 8
3 8 2 8 2 8
x
2
=
x
2
=
x
3
=
9. 10.
x
2
=
8.
x
2
=
9.
x
3
=
10.
Wednesday
Thursday
1.
5.8
–
2.7
=
1.
6.8
–
2.9
=
2.
5.89
–
2.76
=
2.
36.8
–
22.9
=
3.
25.89
–
12.76
=
3.
36.87
–
22.94
=
4.
783
÷
2
=
4.
896
÷
5
=
5.
793
÷
2
=
5.
872
÷
5
=
6.
2x
180
=
20 x
6.
3x
280
=
6x7x
7.
60 x
6
=
10 x 3 x
7.
60 x 7 x
2
=
6x2x7x
8.
2 15 5 15 4 15
x
6
=
8.
x
3
=
x
2
=
9.
x
4
=
x
4
=
10.
6 15 3 15 8 15
x
2
=
9. 10.
Friday 1.
4.5
–
2.7
=
2.
4.53
–
2.79
=
3.
54.53
–
22.79
=
4.
753
÷
5
=
5.
784
÷
5
=
6.
2x
240
=
4x
7.
4 x 10 x
12
=
40 x
8.
3 20 4 20 7 20
x
3
=
x
3
=
x
3
=
9. 10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 89
Ninja challenge
Tom says that there are 5 hundreds in the number 143,671. Is Tom correct? Explain why.
89
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 28 Monday 1.
10%
of
2.
1%
of
3.
10%
of
4.
1%
of
5.
10%
of
6.
1%
of
7.
10%
of
8.
1%
of
9.
10%
of
10.
1%
of
173,000
Tuesday = =
413,000
= =
67,410
85.6
= =
9.5
343.7
= =
5,610
8,400
1.74
= =
0.075
1.
10%
of
2.
1%
of
3.
10%
of
4.
1%
of
5.
10%
of
6.
1%
of
7.
10%
of
8.
1%
of
9.
10%
of
10.
1%
of
Wednesday 1.
10%
of
2.
1%
of
3.
10%
of
4.
1%
of
5.
10%
of
6.
1%
of
7.
10%
of
8.
1%
of
9.
10%
of
10.
1%
of
365,000
=
52.5
= =
23.6
246.7
= =
8,710
4,590
= =
68,460
3.74
= =
0.153
10%
of
2.
1%
of
3.
10%
of
4.
1%
of
5.
10%
of
6.
1%
of
7.
10%
of
8.
1%
of
9.
10%
of
10.
1%
of
952,000
= =
174,000
90
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 90
= 51,250
= =
6,480
91.3
= =
13.6
174.9
2.09
= =
0.062
1.
10%
of
2.
1%
of
3.
10%
of
4.
1%
of
5.
10%
of
6.
1%
of
7.
10%
of
8.
1%
of
9.
10%
of
10.
1%
of
894,000
= =
482,000
= =
71,280
67.2
= =
76.5
517.1
= =
8,250
7,410
8.32
= =
0.236
6,780
Sam doubles 1,800 and then quarters the answer. What number does Sam finish with?
234.8 95.1
= =
63.4
=
= =
6,360
562,000
9,140
= =
63,850
=
Ninja challenge
Friday 1.
=
Thursday =
217,000
245,000
9.16
= =
0.942 Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 29 Monday
Tuesday
1.
31
x
21
=
1.
35
x
13
=
2.
22
x
21
=
2.
21
x
14
=
3.
x
12
=
x
6
=
+
4 6
=
of
28
=
+ +
1 5 1 3
=
8.
1 14 1 13 1 34 5 8 2 6 3 4
equals
9. 10.
4. 5. 6. 7.
x
9
=
3.
x
8
=
4.
+
2 4
=
5.
of
72
=
6.
+
=
7.
+
1 12 1 16
equals
8.
1 14 1 13 2 56 5 7 2 6 2 4
36
÷
6
=
9.
48
÷
8
=
72
÷
6
=
10.
54
÷
9
=
Wednesday
Thursday
1.
20
x
14
=
1.
23
x
22
=
2.
22
x
32
=
2.
14
x
14
=
3.
x
3
=
3.
4
=
x
6
=
4.
x
6
=
+
4 6
=
5.
+
4 5
=
of
32
=
6.
of
27
=
+
=
7.
+
equals
8.
+
2 6 1 8
=
+
1 5 3 8
1 8 1 10 4 45 7 9 1 2 2 4
x
8.
1 6 1 9 2 16 7 8 1 2 1 4
equals
9.
84
÷
7
=
9.
14
÷
7
=
10.
24
÷
6
=
10.
12
÷
3
=
4. 5. 6. 7.
Friday 1.
24
x
21
=
2.
12
x
23
=
3.
x
11
=
x
9
=
+
2 5
=
of
48
=
+ +
2 10 3 12
=
8.
1 12 1 10 4 15 7 8 2 5 2 6
equals
9.
42
÷
7
=
10.
27
÷
3
=
4. 5. 6. 7.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 91
Ninja challenge
Cho counts back 4,000 from 10,304. What number does Cho count back to?
91
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 29 Monday
Tuesday
1.
5.7
–
2.9
=
1.
6.4
–
3.9
=
2.
5.73
–
2.97
=
2.
36.4
–
23.9
=
3.
45.73
–
32.97
=
3.
36.43
–
23.97
=
4.
862
÷
5
=
4.
628
÷
5
=
5.
879
÷
5
=
5.
697
÷
5
=
6.
12 x
50
=
120 x
6.
280 x
2
=
7x4x
7.
3x2x
100
=
30 x 2 x
7.
7x8x
10
=
7 x 40 x
8.
3 25 5 25 7 25
5 27 6 27 4 27
x
5
=
x
4
=
x
7
=
9. 10.
x
8
=
8.
x
3
=
9.
x
4
=
10.
Wednesday
Thursday
1.
6.4
–
3.7
=
1.
7.2
–
4.8
=
2.
6.45
–
3.79
=
2.
37.2
–
24.8
=
3.
106.45
–
43.79
=
3.
37.24
–
24.87
=
4.
123
÷
4
=
4.
279
÷
4
=
5.
134
÷
4
=
5.
283
÷
4
=
6.
2x
330
=
11 x 6 x
6.
2x
180
=
4x
7.
11 x 3 x
20
=
3x2x
7.
6x3x
20
=
6x2x
8.
5 24 4 12 4 29
x
3
=
8.
x
4
=
x
2
=
9.
x
5
=
x
3
=
10.
4 19 6 31 7 33
x
5
=
9. 10.
Friday 1.
8.3
–
2.7
=
2.
8.34
–
2.76
=
3.
78.34
–
22.76
=
4.
453
÷
4
=
5.
487
÷
4
=
6.
4x
180
=
12 x
7.
2x6x
60
=
30 x 6 x
8.
2 13 7 31 8 33
x
6
=
x
4
=
x
4
=
9. 10. 92
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 92
Ninja challenge
Iko says that one quarter of 2,400 is equal to 300 x 3. Is Iko correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 29 Monday 1.
10%
Tuesday 1.
of
645,000
=
2.
=
1%
of
451,000
3.
=
10%
of =
10%
of
714,000
=
2.
=
1%
of
274,000
364,000
3.
=
10%
of
311,000
173.4
4.
1%
of
=
152.7
5.
10%
of
37,370
=
4.
1%
of
5.
10%
of
45,670
=
6.
=
1%
of
7,230
6.
=
1%
of
9,560
7.
=
10%
of
5,110
7.
=
10%
of
1,740
8.
7.61
=
1%
of
8.
2.91
=
1%
of
9.
10%
of
59.2
=
9.
10%
of
75.8
=
=
1%
of
=
1%
of
10.
26.4
10.
Wednesday 1.
10%
77.5
Thursday 1.
of
649,000
=
2.
=
1%
of
525,000
3.
=
10%
of =
10%
of
734,000
=
2.
=
1%
of
498,000
389,000
3.
=
10%
of
617,000
523.5
4.
1%
of
=
612.9
5.
10%
of
18,260
=
4.
1%
of
5.
10%
of
74,370
=
6.
=
1%
of
8,530
6.
=
1%
of
9,830
7.
=
10%
of
2,360
7.
=
10%
of
4,510
8.
7.32
=
1%
of
8.
6.18
=
1%
of
9.
10%
of
66.2
=
9.
10%
of
87.1
=
=
1%
of
=
1%
of
10.
92.6
10%
of
561,000
=
2.
=
1%
of
617,000
3.
=
10%
of
175,000
=
532.1
4.
1%
of
5.
10%
of
23,370
=
6.
=
1%
of
7,380
7.
=
10%
of
8,370
8.
7.72
=
1%
of
9.
10%
of
91.9
=
=
1%
of
10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 93
63.1
Ninja challenge
Friday 1.
10.
Tom says that 90,110 less than 100,000 is 10,990. Is Tom correct? Explain why.
71.2 93
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 30 Monday 1.
24
2.
7.
2 12 2 3 1 15 7 8 2 5 3 6
8.
x
21
Tuesday =
1.
23
x
32
=
x
4
=
x
6
=
+
4 5
=
of
72
=
+
=
+
1 15 6 12
equals
x
4
=
2.
x
4
=
3.
+
2 5
=
4.
of
16
=
5.
+
=
6.
+
2 15 2 12
equals
7.
2 9 2 4 1 45 2 6 3 5 1 3
23,172
–
14,283
=
8.
21,207
–
16,028
=
9.
13.45
–
3.5
=
9.
22.38
–
7.4
=
10.
5
+
3.45
=
10.
9
+
2.34
=
3. 4. 5. 6.
Wednesday 1.
24
2.
7.
2 11 2 5 1 57 2 7 2 5 1 4
8.
x
17
Thursday =
1.
26
x
23
=
x
3
=
x
9
=
+
6 7
=
of
108
=
+
=
+
3 14 2 3
equals
x
5
=
2.
x
6
=
3.
+
6 7
=
4.
of
49
=
5.
+
=
6.
+
3 10 2 6
equals
7.
3 14 2 14 1 17 5 9 2 7 1 4
34,189
–
27,482
=
8.
40,382
–
19,288
=
9.
31.23
–
8.9
=
9.
22.94
–
13.3
=
10.
11
+
9.83
=
10.
17
+
4.75
=
3. 4. 5. 6.
Friday 1.
17
x
24
=
2.
x
2
=
x
3
=
+
2 6
=
of
72
=
+ +
1 15 2 3
=
7.
4 14 7 14 1 46 6 9 2 3 1 5
equals
8.
23,285
–
18,049
=
9.
30.09
–
26.4
=
10.
20
+
11.64
=
3. 4. 5. 6.
94
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 94
Ninja challenge
Tom shares 420 by 10. Sam shares 600 by 10. Iko shares 310 by 10. They agree that all of their answers are less than 50. Are they correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 30 Monday
Tuesday
1.
3
–
0.65
=
1.
6
–
1.56
=
2.
3.56
–
0.65
=
2.
6.21
–
1.56
=
3.
0.65
+
3.74
=
3.
1.56
+
5.55
=
4.
373
÷
2
=
4.
886
÷
4
=
5.
373
÷
5
=
5.
886
÷
5
=
÷
4
=
128
6.
÷
4
=
62
÷
5
=
325
7.
÷
5
=
321
x
5
=
x
8
=
x
9
=
6. 7. 8. 9. 10.
3 8 2 7 4 9
x
5
=
8.
x
5
=
9.
x
3
=
10.
4 7 3 16 2 15
Wednesday
Thursday
1.
8
–
0.42
=
1.
7
–
2.68
=
2.
8.34
–
0.42
=
2.
7.12
–
2.68
=
3.
0.44
+
7.82
=
3.
4.34
+
2.46
=
4.
753
÷
4
=
4.
863
÷
2
=
5.
753
÷
5
=
5.
863
÷
5
=
6.
÷
3
=
256
6.
÷
7
=
93
7.
÷
8
=
214
7.
÷
8
=
34
x
3
=
8.
x
3
=
x
5
=
9.
x
5
=
x
5
=
10.
x
3
=
8. 9. 10.
6 15 5 18 6 25
Ninja challenge
Friday 1.
8
–
4.32
=
2.
8.23
–
4.32
=
3.
3.81
+
4.82
=
4.
861
÷
2
=
5.
861
÷
5
=
÷
3
=
674
÷
9
=
114
x
4
=
x
6
=
x
3
=
6. 7. 8. 9. 10.
6 19 3 7 7 13
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 95
3 19 4 7 6 11
Tom multiplies 231 by 24. What answer does Tom get?
95
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 30 Monday 1.
10%
Tuesday 1.
of
671,000
=
2.
=
1%
of
56,460
3.
=
1%
of =
10%
of
583,000
=
2.
=
1%
of
71,270
891
3.
=
1%
of
628
10.42
4.
10%
of
=
12.14
4.
10%
of
5.
50%
of
360
=
5.
50%
of
570
=
6.
50%
of
5,400
=
6.
50%
of
6,300
=
7.
25%
of
860
=
7.
25%
of
920
=
8.
25%
of
2,400
=
8.
25%
of
2,800
=
9.
25%
of
600
=
9.
20%
of
420
=
10.
25%
of
340
=
10.
20%
of
620
=
Wednesday 1.
10%
Thursday 1.
of
739,000
=
2.
=
1%
of
47,320
3.
=
1%
of =
10%
of
371,000
=
2.
=
1%
of
89,730
533
3.
=
1%
of
716
17.43
4.
10%
of
=
24.13
4.
10%
of
5.
50%
of
190
=
5.
50%
of
370
=
6.
50%
of
2,700
=
6.
50%
of
3,100
=
7.
25%
of
760
=
7.
25%
of
940
=
8.
25%
of
3,300
=
8.
25%
of
5,400
=
9.
20%
of
690
=
9.
20%
of
730
=
10.
20%
of
270
=
10.
20%
of
1,240
=
Ninja challenge
Friday 1.
10%
of
742,000
=
2.
=
1%
of
64,270
3.
=
1%
of
561
=
17.25
4.
10%
of
5.
50%
of
570
=
6.
50%
of
3,700
=
7.
25%
of
1,260
=
8.
25%
of
2,480
=
9.
20%
of
970
=
10.
20%
of
1,680
=
96
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 96
What number does Cho multiply 9,000 by to get an answer of 108,000?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 31 Monday 1.
25
2.
7.
2 6 7 9 1 24 3 9 2 5 2 6
8.
x
33
Tuesday =
1.
19
x
26
=
x
4
=
x
2
=
+
4 7
=
of
56
=
+
=
+
2 4 4 16
equals
x
2
=
2.
x
3
=
3.
+
3 4
=
4.
of
36
=
5.
+
=
6.
+
3 15 4 12
equals
7.
2 10 7 11 2 67 6 8 2 8 2 8
21,263
+
18,273
=
8.
61,374
+
25,304
=
9.
21.26
+
17.26
=
9.
31.26
+
9.06
=
10.
20
–
11.64
=
10.
30
–
14.05
=
3. 4. 5. 6.
Wednesday 1.
42
2.
7.
3 10 4 11 2 23 5 7 1 2 2 8
8.
x
23
Thursday =
1.
43
x
17
=
x
5
=
x
3
=
+
5 11
=
of
72
=
+
=
+
2 10 3 16
equals
x
3
=
2.
x
3
=
3.
+
2 3
=
4.
of
84
=
5.
+
=
6.
+
2 10 7 16
equals
7.
2 12 5 11 2 10 11 6 9 1 5 1 8
65,938
+
31,293
=
8.
104,283
+
90,384
=
9.
43.05
+
12.83
=
9.
45.04
+
13.83
=
10.
32
–
12.38
=
10.
41
–
15.32
=
3. 4. 5. 6.
Friday 1.
25
x
41
=
2.
x
9
=
x
6
=
+
3 12
=
of
77
=
+ +
3 10 7 16
=
7.
1 12 3 15 2 10 12 6 11 3 5 4 8
equals
8.
120,389
+
101,823
=
9.
56.76
+
12.55
=
10.
47
–
21.54
=
3. 4. 5. 6.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 97
Ninja challenge
Tom states that 7,000 less than 36,000 is greater than 28,000. Is Tom correct? Explain why.
97
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 31 Monday
Tuesday
1.
5
–
1.16
=
1.
8
–
1.34
=
2.
5.10
–
1.16
=
2.
8.21
–
1.34
=
3.
3.24
+
1.46
=
3.
6.47
+
1.64
=
4.
783
÷
2
=
4.
891
÷
5
=
5.
783
÷
4
=
5.
891
÷
4
=
÷
8
=
129
6.
÷
3
=
458
÷
7
=
254
7.
÷
8
=
153
x
3
=
x
4
=
x
8
=
6. 7. 8. 9. 10.
2 9 4 11 5 13
x
7
=
8.
x
6
=
9.
x
3
=
10.
5 9 6 17 3 13
Wednesday
Thursday
1.
9
–
2.56
=
1.
8
–
1.56
=
2.
9.13
–
2.56
=
2.
8.23
–
1.56
=
3.
2.76
+
6.37
=
3.
6.37
+
4.46
=
4.
963
÷
5
=
4.
743
÷
5
=
5.
963
÷
2
=
5.
743
÷
2
=
6.
÷
7
=
536
6.
÷
9
=
152
7.
÷
6
=
245
7.
÷
4
=
135
x
4
=
8.
x
4
=
x
9
=
9.
x
9
=
x
7
=
10.
x
5
=
8. 9. 10.
3 11 2 17 5 13
Ninja challenge
Friday 1.
10
–
3.67
=
2.
10.23
–
3.67
=
3.
6.36
+
6.77
=
4.
653
÷
5
=
5.
653
÷
2
=
÷
7
=
248
÷
8
=
325
x
6
=
x
5
=
x
5
=
6. 7. 8. 9. 10.
3 17 5 19 6 23
98
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 98
5 18 4 17 5 19
Cho states that 50 times 160 is equal to 80 multiplied by 100. Is Cho correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 31 Monday 1.
1%
Tuesday 1.
of
109,000
=
2.
=
10%
of
57,190
3.
=
10%
of =
4.
1%
of
5.
50%
of
490
=
=
50%
of
of
1,480
=
=
25%
of
of
1,230
=
=
20%
of
6. 7.
25%
8. 9.
20%
10.
1%
of
119,000
=
2.
=
10%
of
61,840
68.6
3.
=
10%
of
81.9
13.64
4.
1%
of
=
20.45
5.
50%
of
570
=
=
50%
of
of
2,468
=
=
25%
of
of
2,450
=
=
20%
of
2,100
6. 7.
188
8. 9.
2,150
25% 20%
10.
Wednesday 1.
1%
1.
391,000
=
2.
=
10%
of
78,340
3.
=
10%
of =
4.
1%
of
5.
50%
of
1,260
=
=
50%
of
of
2,840
=
=
25%
of
of
20
=
=
20%
of
7.
25%
8. 9.
20%
10.
1%
=
2.
=
10%
of
91,280
104.5
3.
=
10%
of
111.1
35.71
4.
1%
of
=
50.67
5.
50%
of
2,050
=
=
50%
of
of
44
=
=
25%
of
of
47
=
=
20%
of
4,700 180 122
=
10%
of
87,400
3.
=
10%
of
145.3
=
75.03
5.
50%
of
3,750
=
=
50%
of
of
64
=
=
25%
of
of
87
=
=
20%
of
7.
25%
8. 9. 10.
20%
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 99
10.
20%
7,450 36 178
Ninja challenge
2.
of
25%
8. 9.
=
1%
6. 7.
703,000
4.
1%
543,000
of
6.
2,670
of
Friday 1.
264
Thursday
of
6.
3,300
Iko tells Sam that 270 is equal to 37 of 630. Is Iko correct? Explain why.
8,272 84 204 99
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 32 Monday
Tuesday
1.
25
x
41
=
1.
17
x
16
=
2.
0.45
x
1,000
=
2.
0.19
x
1,000
=
3.
2.1
÷
10
=
3.
6.7
÷
10
=
4.
266
÷
7
=
4.
294
÷
7
=
5.
224
÷
8
=
5.
280
÷
8
=
6.
5
–
1.53
=
6.
7
–
4.08
=
7.
4 9 3 9 5 12 5 212
7.
4 6 2 5 4 15 1 56
of
42
=
+
3 20
equals
x
3
=
+
4 6
=
8. 9. 10.
of
108
+
3 18
= equals
8.
x
2
=
9.
+
8 12
=
10.
Wednesday
Thursday
1.
19
x
23
=
1.
22
x
32
=
2.
0.41
x
1,000
=
2.
0.78
x
1,000
=
3.
8.5
÷
10
=
3.
9.2
÷
10
=
4.
336
÷
7
=
4.
371
÷
7
=
5.
304
÷
8
=
5.
344
÷
8
=
6.
9
–
3.17
=
6.
8
–
5.32
=
7.
7 9 4 5 4 18 1 36
of
45
=
7.
of
63
=
+
1 20
equals
8.
+
5 14
equals
x
3
=
9.
x
8
=
+
5 6
3 9 4 7 2 20 1 39
+
8 9
=
8. 9. 10.
=
Friday 1.
25
x
17
=
2.
0.56
x
1,000
=
3.
7.1
÷
10
=
4.
392
÷
7
=
5.
384
÷
8
=
6.
7
–
1.38
=
7.
8 9 1 4 3 20 1 59
of
81
=
+
1 3
equals
x
6
=
+
5 9
=
8. 9. 10. 100
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 100
10.
Ninja challenge
Sam divides 36 by 9 and gets the answer of 4. If Sam divides 3,600 by 9, what answer will he get?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 32 Monday
Tuesday
1.
5
–
2.43
=
1.
17
–
5.64
=
2.
5.16
–
2.43
=
2.
17.05
–
5.64
=
3.
2.83
+
2.73
=
3.
11.71
+
6.84
=
4.
453
÷
4
=
4.
785
÷
4
=
5.
453
÷
5
=
5.
785
÷
2
=
÷
3
=
356
6.
÷
3
=
695
÷
7
=
109
7.
÷
9
=
235
x
5
=
x
6
=
x
4
=
6. 7. 8. 9. 10.
3 17 2 9 4 19
x
6
=
8.
x
5
=
9.
x
6
=
10.
5 17 3 14 5 19
Wednesday
Thursday
1.
23
–
6.43
=
1.
58
–
9.54
=
2.
23.14
–
6.43
=
2.
58.23
–
9.54
=
3.
15.31
+
4.23
=
3.
45.39
+
4.34
=
4.
951
÷
4
=
4.
893
÷
2
=
5.
951
÷
5
=
5.
893
÷
5
=
6.
÷
7
=
251
6.
÷
9
=
235
7.
÷
8
=
218
7.
÷
7
=
153
x
6
=
8.
x
5
=
x
7
=
9.
x
5
=
x
9
=
10.
x
4
=
8. 9. 10.
3 13 4 25 5 28
Ninja challenge
Friday 1.
36
–
23.56
=
2.
36.15
–
23.56
=
3.
12.39
+
13.06
=
4.
829
÷
4
=
5.
829
÷
5
=
÷
8
=
441
÷
7
=
215
x
4
=
x
3
=
x
3
=
6. 7. 8. 9. 10.
3 7 8 23 7 18
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 101
2 7 6 25 5 18
Sam shares 98,000 equally into 7 groups. What will each group be equal to?
101
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 32 Monday 1.
1%
Tuesday 1.
of
59,372
=
=
10%
of
of
384
=
4.
=
25%
of
124
5.
=
20%
of
142
÷
10
=
=
26.2
÷
x
100
=
=
11,100
x
is
equal
to
2. 3.
6.
50%
3,543
7. 8.
101
9. 10.
33
7,460
of
68,382
=
=
10%
of
of
584
=
4.
=
25%
of
132
5.
=
20%
of
135
÷
10
=
=
51.2
÷
x
100
=
=
1,010
x
is
equal
to
2. 3.
6. 10
50%
6,471
7. 8.
10
1%
203
9. 10.
23
Wednesday 1.
1%
1.
101,283
=
=
10%
of
of
628
=
4.
=
25%
of
148
5.
=
20%
of
160
÷
10
=
=
16.1
÷
x
100
=
=
10.1
x
is
equal
to
3.
6.
50%
608.3
7. 8.
11.1
9. 10.
43
7,850
1%
10
=
10%
of
of
802
=
4.
=
25%
of
188
5.
=
20%
of
240
÷
10
=
=
304.2
÷
x
100
=
=
10.10
x
is
equal
to
6.
63
7. 8.
100.1
9. 10.
63
102
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 102
10%
of
of
752
=
4.
=
25%
of
168
5.
=
20%
of
220
÷
10
=
=
251.3
÷
x
100
=
=
4.56
x
is
equal
to
50%
61.7
7. 10.11
9. 53
1,010
10 10
Ninja challenge
=
50%
=
2.
10.
230,000
3.
=
8. 10
1%
105,380
6.
of
2.
10
of
3.
Friday 1.
10
Thursday
of
2.
9,140
1,001
If Tom has 120 groups of 800, how many does he have in total?
10 10
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 33 Monday
Tuesday
1.
320
÷
10
=
1.
450
÷
10
=
2.
10%
of
320
=
2.
10%
of
450
=
3.
45
÷
10
=
3.
31
÷
10
=
4.
10%
of
45
=
4.
10%
of
31
=
5.
50%
of
100
=
5.
50%
of
200
=
6.
50%
of
20
=
6.
50%
of
40
=
7.
1 13 2 4 2 20 9 112
7.
1 14 2 5 2 20 9 110
x
2
=
+
1 3
equals
x
5
=
+
5 10
=
8. 9. 10.
x
2
+
1 3
= equals
8.
x
9
=
9.
+
5 12
=
10.
Wednesday
Thursday
1.
720
÷
10
=
1.
620
÷
10
=
2.
10%
of
720
=
2.
10%
of
620
=
3.
67
÷
10
=
3.
59
÷
10
=
4.
10%
of
67
=
4.
10%
of
59
=
5.
50%
of
400
=
5.
50%
of
600
=
6.
50%
of
80
=
6.
50%
of
120
=
7.
1 16
x
2
=
7.
x
2
=
+
6 18
1 110
equals
8.
+
6 12
equals
x
11
=
9.
x
7
=
+
6 10
+
3 5
=
8. 9. 10.
2 6 2 23 5 110
=
Friday 1.
980
÷
10
=
2.
10%
of
980
=
3.
71
÷
10
=
4.
10%
of
71
=
5.
50%
of
800
=
6.
50%
of
140
=
7.
1 112 1 3 2 10 1 35
x
2
=
+
6 12
equals
x
3
=
+
4 5
=
8. 9. 10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 103
10.
2 6 2 17 1 35
Ninja challenge
Cho says that 60 x 7 is greater than 400. Is Cho correct? Explain why.
103
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 33 Monday
Tuesday
1.
6.4
+
2.34
=
1.
3.8
+
4.56
=
2.
6.54
+
2.43
=
2.
4.26
+
4.6
=
3.
456
÷
10
=
3.
346
÷
10
=
4.
456
÷
100
=
4.
346
÷
100
=
5.
10%
of
456
=
5.
10%
of
346
=
6.
1%
of
456
=
6.
1%
of
346
=
7.
1²
is
equal
to
7.
2²
is
equal
to
8.
√1
is
equal
to
8.
√4
is
equal
to
9.
1 28 2 18
1 110 2 110
x
4
=
x
4
=
10.
x
3
=
9.
x
3
=
10.
Wednesday
Thursday
1.
2.5
+
5.78
=
1.
7.85
+
5.6
=
2.
5.3
+
2.38
=
2.
5.35
+
7.4
=
3.
45
÷
10
=
3.
37
÷
10
=
4.
45
÷
100
=
4.
37
÷
100
=
5.
10%
of
45
=
5.
10%
of
37
=
6.
1%
of
45
=
6.
1%
of
37
=
7.
3²
is
equal
to
7.
4²
is
equal
to
8.
√9
is
equal
to
8.
√16
is
equal
to
9.
3 117 3 117
3 215 3 215
x
2
=
x
3
=
10.
x
2
=
9.
x
4
=
10.
Friday 1.
6.7
+
4.67
=
2.
6.37
+
5.8
=
3.
607
÷
10
=
4.
607
÷
100
=
5.
10%
of
607
=
6.
1%
of
607
=
7.
5²
is
equal
to
8.
√25
is
equal
to
9.
4 217
x
3
=
x
4
=
10.
4 217
104
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 104
Ninja challenge
Tom says that 0.39 less than 2.83 is equal to 2.44. Is Tom correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 33 Monday 1.
1%
Tuesday 1.
of
34
=
2.
=
10%
of
106
3.
=
20%
of
4.
=
17,560
5.
=
6.
18.4
7. 8. 9. 10.
2 35 6 12 3 4
1%
of
341
=
2.
=
10%
of
194
34
3.
=
20%
of
62
÷
10
4.
=
13,000
÷
10
32,200
x
10
5.
=
14,900
x
10
+
8.45
=
+
7.67
=
=
29.1
–
=
32.5
–
x
4
=
x
5
=
+
2 3
=
6. 7.43
20.9
7.
x
3
=
8.
x
3
=
9.
+
2 5
=
10.
2 27 7 13 5 6
Wednesday 1.
1%
Thursday 1.
of
672.1
=
2.
=
10%
of
201
3.
=
20%
of
4.
=
349
5.
=
6.
143.53
7. 8. 9. 10.
2 14 9 16 7 8
1%
56.7
=
2.
=
10%
of
357
74
3.
=
20%
of
81
÷
10
4.
=
717
÷
10
23,500
x
10
5.
=
17,600
x
10
+
23.4
=
+
19.54
=
=
120.3
–
=
130.6
–
x
5
=
x
2
=
x
8
=
+
11 12
=
x
5
+
1 2
6. 9.34
9.
=
10.
=
=
2.
=
10%
of
412
3.
=
20%
of
97
4.
=
941
÷
10
5.
=
23,100
x
10
+
16.41
=
=
143.2
–
x
2
=
x
4
=
+
13 14
=
7. 8. 9. 10.
2 37 7 11 4 7
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 105
4 34 4 9 5 6
31.93
Ninja challenge
103.5
94.3
104.5
7. 8.
of
6.
1%
of
Friday 1.
6.98
Tom tells Sam that 4,600 is equal to 67 of 5,600. Is Tom correct? Explain why.
45.31
105
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 34 Monday
Tuesday
1.
34
÷
10
=
1.
22
÷
10
=
2.
10%
of
34
=
2.
10%
of
22
=
3.
710
÷
10
=
3.
250
÷
10
=
4.
10%
of
710
=
4.
10%
of
250
=
5.
50%
of
800
=
5.
50%
of
1,000
=
6.
50%
of
140
=
6.
50%
of
180
=
7.
25%
of
100
=
7.
25%
of
40
=
8.
25%
of
80
=
8.
25%
of
20
=
9.
1,350
÷
10
=
9.
1,460
÷
10
=
10.
10%
of
1,350
=
10.
10%
of
1,460
=
Wednesday
Thursday
1.
47
÷
10
=
1.
56
÷
10
=
2.
10%
of
47
=
2.
10%
of
56
=
3.
390
÷
10
=
3.
550
÷
10
=
4.
10%
of
390
=
4.
10%
of
550
=
5.
50%
of
2,000
=
5.
50%
of
48
=
6.
50%
of
500
=
6.
50%
of
32
=
7.
25%
of
200
=
7.
25%
of
80
=
8.
25%
of
24
=
8.
25%
of
8
=
9.
2,130
÷
10
=
9.
3,450
÷
10
=
10.
10%
of
2,130
=
10.
10%
of
3,450
=
Friday 1.
98
÷
10
=
2.
10%
of
98
=
3.
610
÷
10
=
4.
10%
of
610
=
5.
50%
of
18
=
6.
50%
of
36
=
7.
25%
of
16
=
8.
25%
of
36
=
9.
1,280
÷
10
=
10.
10%
of
1,280
=
106
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 106
Ninja challenge
Sam doubles 500 and tells Tom this is equal to 100 x 10. Is Sam correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 34 Monday
Tuesday
1.
4.6
+
3.53
=
1.
3.45
+
6.8
=
2.
4.58
+
3.5
=
2.
3.4
+
6.35
=
3.
567
÷
10
=
3.
800
÷
10
=
4.
567
÷
100
=
4.
800
÷
100
=
5.
10%
of
567
=
5.
10%
of
800
=
6.
1%
of
567
=
6.
1%
of
800
=
7.
6²
is
equal
to
7.
7²
is
equal
to
8.
√36
is
equal
to
8.
√49
is
equal
to
9.
2 19 2 19
2 213 2 213
x
4
=
x
5
=
10.
x
3
=
9.
x
4
=
10.
Wednesday
Thursday
1.
7.5
+
4.67
=
1.
3.67
+
6.4
=
2.
7.65
+
4.6
=
2.
3.8
+
6.27
=
3.
780
÷
10
=
3.
850
÷
10
=
4.
780
÷
100
=
4.
850
÷
100
=
5.
10%
of
780
=
5.
10%
of
850
=
6.
1%
of
780
=
6.
1%
of
850
=
7.
8²
is
equal
to
7.
9²
is
equal
to
8.
√64
is
equal
to
8.
√81
is
equal
to
9.
1 217 1 217
1 211 1 211
x
3
=
x
5
=
10.
x
5
=
9.
x
6
=
10.
Friday 1.
7.8
+
4.67
=
2.
7.07
+
4.7
=
3.
789
÷
10
=
4.
789
÷
100
=
5.
10%
of
789
=
6.
1%
of
789
=
7.
10²
is
equal
to
8.
√100
is
equal
to
9.
3 213
x
2
=
x
4
=
10.
3 213
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 107
Ninja challenge
Iko adds 9.44 to 1.34. Iko says her answer is greater than 11. Is Iko correct? Explain why.
107
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 34 Monday
Tuesday
1.
10%
of
2.
4.82
=
3.
102.3
=
÷
4.
0.4
=
5.
12.56
+
6.
12.16
=
7.
1 57 2 4 1 2 1 3
8. 9. 10.
1.
10%
of
2.
5.06
=
10
3.
230
=
÷
10
x
10
4.
1.6
=
x
10
=
13.51
5.
13.53
+
=
14.16
6.
14.71
=
20.31
–
1 56 3 5 3 4 1 3
x
3
=
x
7
=
–
5 12 5 9
=
= 1%
13.56
154.1
of
–
x
3
=
7.
x
8
=
8.
–
5 14 5 12
+
=
9.
=
10.
Wednesday 10%
of
2.
7.15
=
3.
190
=
÷
4.
3.7
=
5.
12.91
+
6.
15.19
=
21.6
7.
1 29
x
9. 10.
4 5 2 3 2 3
of
2.
8.02
=
10
3.
96.4
=
÷
10
x
10
4.
4.5
=
x
10
=
14.64
5.
13.4
+
=
15.94
–
6.
21.99
=
30.4
–
3
=
7.
2 19
x
4
=
x
9
=
8.
x
5
=
–
5 9 5 6
–
2 3 2 3
=
+
1%
of
=
9.
=
10.
10%
of
2.
9.83
=
3.
127
=
÷
10
4.
1.6
=
x
10
5.
20.4
+
=
27.71
6.
17.29
=
26.8
–
7.
1 17 4 7 7 8 4 6
x
6
=
x
5
=
–
3 4 7 18
=
10.
=
10%
20.5
1.
9.
of
1.
=
Friday
8.
1%
17.3
Thursday
1.
8.
+
=
+
= 1%
108
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 108
27.4
of
3 8 8 9 4 5
+
= 1%
31.7
of
=
Ninja challenge
Cho says that if she doubles the numbers 20,000 and 30,000, the difference between the answers is 10,000. Is Cho correct? Explain why.
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 35 Monday
Tuesday
1.
10%
of
54
=
1.
10%
of
73
=
2.
10%
of
3.2
=
2.
10%
of
1.9
=
3.
10%
of
17
=
3.
10%
of
33
=
4.
10%
of
430
=
4.
10%
of
570
=
5.
10%
of
672
=
5.
10%
of
352
=
6.
10%
of
1,260
=
6.
10%
of
1,840
=
7.
50%
of
20
=
7.
50%
of
120
=
8.
50%
of
80
=
8.
50%
of
220
=
9.
25%
of
100
=
9.
25%
of
60
=
10.
25%
of
160
=
10.
25%
of
48
=
Wednesday
Thursday
1.
10%
of
61
=
1.
10%
of
19
=
2.
10%
of
7.3
=
2.
10%
of
91
=
3.
10%
of
89
=
3.
10%
of
49
=
4.
10%
of
140
=
4.
10%
of
620
=
5.
10%
of
613
=
5.
10%
of
752
=
6.
10%
of
2,370
=
6.
10%
of
2,890
=
7.
50%
of
420
=
7.
50%
of
460
=
8.
50%
of
800
=
8.
50%
of
1,200
=
9.
25%
of
4,000
=
9.
25%
of
600
=
10.
25%
of
2,000
=
10.
25%
of
4
=
Friday 1.
10%
of
27
=
2.
10%
of
73
=
3.
10%
of
56
=
4.
10%
of
740
=
5.
10%
of
745
=
6.
10%
of
3,470
=
7.
50%
of
18
=
8.
50%
of
34
=
9.
25%
of
24
=
10.
25%
of
64
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 109
Ninja challenge
Cho says that the difference between 14,374 and 12,000 is greater than 4,000. Is Cho correct? Explain why.
109
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 35 Monday
Tuesday
1.
6.2
–
3.67
=
1.
8.34
–
3.7
=
2.
6.67
–
3.2
=
2.
8.7
–
3.34
=
3.
100%
of
200
=
3.
100%
of
400
=
4.
50%
of
200
=
4.
50%
of
400
=
5.
25%
of
200
=
5.
25%
of
400
=
6.
20%
of
200
=
6.
20%
of
400
=
7.
11²
is
equal
to
7.
12²
is
equal
to
8.
√121
is
equal
to
8.
√144
is
equal
to
9.
1 25 1 45
2 27 2 27
x
3
=
x
5
=
10.
x
4
=
9.
x
4
=
10.
Wednesday
Thursday
1.
9.6
–
4.28
=
1.
8.39
–
5.3
=
2.
9.28
–
4.6
=
2.
8.3
–
5.39
=
3.
100%
of
500
=
3.
100%
of
440
=
4.
50%
of
500
=
4.
50%
of
440
=
5.
25%
of
500
=
5.
25%
of
440
=
6.
20%
of
500
=
6.
20%
of
440
=
7.
1³
is
equal
to
7.
2³
is
equal
to
is equal to
8.
The cube root of 8 1 13 2 13
8.
The cube root of 1
9.
2 18 2 18
10.
x
2
=
9.
x
5
=
10.
Friday 1.
5.8
–
3.43
=
2.
5.43
–
3.8
=
3.
100%
of
240
=
4.
50%
of
240
=
5.
25%
of
240
=
6.
20%
of
240
=
7.
3³
is
equal
to
8.
The cube root of 27
9.
1 25
10.
1 25
3
=
x
4
=
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 110
x
4
=
x
4
=
Ninja challenge
Cho divides 1,460 by 4. What is her answer?
is equal to
x
110
is equal to
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 35 Monday 1.
243
2.
Tuesday 1.
x
32
=
=
1,687
÷
7
2.
189
x
42
=
=
2,088
÷
8
3.
13.7
=
÷
100
3.
17.2
=
÷
100
4.
180
=
x
1,000
4.
280
=
x
1,000
5.
72,371
+
=
85,405
5.
81,261
+
=
110,295
6.
66.55
=
6.
34.83
=
80
–
7.
1 15 3 9 5 6 5 10
1 36 5 6 8 9 4 5
x
3
=
x
2
=
–
2 3 3 7
=
8. 9. 10.
90
–
x
4
=
7.
x
5
=
8.
–
3 12 4 5
+
=
9.
=
10.
Wednesday 1.
372
2.
+
=
Thursday 1.
x
52
=
=
2,106
÷
9
2.
473
x
67
=
=
3,240
÷
8
3.
35.9
=
÷
100
3.
83.8
=
÷
100
4.
750
=
x
1,000
4.
1,540
=
x
1,000
5.
94,371
+
=
168,383
5.
105,412
+
=
203,757
6.
44.69
=
120
–
6.
51.95
=
150
–
7.
1 15
x
5
=
7.
2 14
x
3
=
x
3
=
8.
x
3
=
–
3 5 2 5
–
4 5 2 3
=
8. 9. 10.
6 9 8 10 9 10
+
=
9.
=
10.
512
2.
x
72
=
=
3,934
÷
7
3.
117
=
÷
100
4.
3,170
=
x
1,000
5.
104,899
+
=
203,903
6.
98.46
=
200
–
7.
3 13 6 15 13 18 9 10
x
2
=
x
3
=
–
1 3 4 5
=
8. 9. 10.
+
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 111
+
=
Ninja challenge
Friday 1.
4 10 13 15 9 12
Iko says that the difference between 706,328 and 805,265 is 90,572. Is Iko correct? Explain why.
= 111
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 36 Monday
Tuesday
1.
10%
of
345
=
1.
10%
of
603
=
2.
10%
of
5
=
2.
10%
of
14
=
3.
10%
of
15
=
3.
10%
of
76
=
4.
10%
of
105
=
4.
10%
of
119
=
5.
50%
of
32
=
5.
50%
of
64
=
6.
25%
of
44
=
6.
25%
of
80
=
7.
2 14 2 26 2 5 4 5
7.
3 34 3 26 2 6 3 5
x
2
=
+
=
+
5 6 1 2
x
3
=
8. 9. 10.
x
3
+
=
8.
+
5 6 2 6
= =
9.
x
3
=
10.
Wednesday
=
Thursday
1.
10%
of
746
=
1.
10%
of
193
=
2.
10%
of
9
=
2.
10%
of
7
=
3.
10%
of
124
=
3.
10%
of
1,270
=
4.
10%
of
463
=
4.
10%
of
847
=
5.
50%
of
68
=
5.
50%
of
28
=
6.
25%
of
120
=
6.
25%
of
60
=
7.
1 57
x
2
=
7.
x
3
=
+
=
8.
+
=
9.
+
7 8 2 6
=
+
3 5 2 4
2 27
x
3
=
10.
x
3
=
8. 9. 10.
1 45 2 8 5 7
Friday 1.
10%
of
204
=
2.
10%
of
134
=
3.
10%
of
1,550
=
4.
10%
of
305
=
5.
50%
of
46
=
6.
25%
of
52
=
7.
1 17 1 46 6 12 6 12
x
2
=
+
=
+
4 6 1 4
x
3
=
8. 9. 10. 112
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 112
1 48 3 12 6 8
=
Ninja challenge
Iko says that 76 groups of 8 is equal to 600. Is Iko correct?
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 36 Monday
Tuesday
1.
67.6
–
4.78
=
1.
75.89
–
4.9
=
2.
67.78
–
4.6
=
2.
75.9
–
4.89
=
3.
100%
of
480
=
3.
100%
of
1,000
=
4.
50%
of
480
=
4.
50%
of
1,000
=
5.
25%
of
480
=
5.
25%
of
1,000
=
6.
20%
of
480
=
6.
20%
of
1,000
=
7.
4³
is
equal
to
7.
5³
is
equal
to
is equal to
8.
The cube root of 125 2 111
8.
The cube root of 64
9.
1 29
10.
1 29
x
3
=
9.
x
4
=
10.
2 111
Wednesday
is equal to
x
6
=
x
9
=
Thursday
1.
62.4
–
8.78
=
1.
34.5
–
8.98
=
2.
62.78
–
8.4
=
2.
34.98
–
8.5
=
3.
100%
of
720
=
3.
100%
of
60
=
4.
50%
of
720
=
4.
50%
of
60
=
5.
25%
of
720
=
5.
25%
of
60
=
6.
20%
of
720
=
6.
20%
of
60
=
7.
1x1x1
=
=
1³
7.
2x2x2
=
=
2³
8.
2x2x2
=
=
2³
8.
3x3x3
=
=
3³
9.
1 25 1 25
2 15 2 15
x
4
=
x
6
=
10.
x
3
=
9.
x
6
=
10.
Ninja challenge
Friday 1.
64.35
–
5.9
=
2.
64.9
–
5.35
=
3.
100%
of
600
=
4.
50%
of
600
=
5.
25%
of
600
=
6.
20%
of
600
=
7.
3x3x3
=
=
3³
8.
4x4x4
=
=
4³
9.
2 14
x
5
=
x
7
=
10.
2 14
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 113
Iko divides 3,600 by 1,000. Iko says her answer is 36. Is Iko correct? Explain why.
113
15/09/2022 09:59
v
GRAND MASTER LEVEL
WEEK 36 Monday
Tuesday
1.
=
65
x
476
1.
=
69
x
525
2.
=
2,202
÷
3
2.
=
3,228
÷
4
3.
=
340,000
÷
100
3.
=
76,000
÷
100
4.
=
0.04
x
1,000
4.
=
0.61
x
1,000
5.
+
12.5
=
58.12
5.
+
23.5
=
84.95
=
20
–
12.31
6.
=
40
–
29.34
x
2
=
x
4
=
+
1 38 1 15
=
6. 7. 8. 9. 10.
2 14 7 9 1 24 9 210
x
2
=
7.
x
3
=
8.
+
1 13 1 45
–
=
9.
=
10.
1 19 4 12 1 14 4 210
Wednesday
–
=
Thursday
1.
=
75
x
632
1.
=
82
x
673
2.
=
4,555
÷
5
2.
=
4,992
÷
6
3.
=
4,900
÷
100
3.
=
751
÷
100
4.
=
1.56
x
1,000
4.
=
2.56
x
100
5.
+
32.3
=
104.62
5.
+
17.4
=
85.33
6.
=
50
–
31.05
6.
=
90
–
67.32
x
2
=
7.
x
2
=
x
5
=
8.
x
2
=
+
1 38 1 19
+
1 13 1 14
=
7. 8. 9. 10.
1 26
4 9 2 24 3 13
–
=
9.
=
10.
Friday 1.
=
93
x
739
2.
=
4,935
÷
7
3.
=
406
÷
100
4.
=
10.45
x
100
5.
+
31.7
=
102.26
=
80
–
12.54
x
3
=
x
3
=
+
1 23
=
6. 7. 8. 9. 10.
2 15 5 8 2 13 3 89
–
1 19
114
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 114
1 56
8 9 1 89 2 23
–
=
Ninja challenge
Cho tells Sam that 2,000 is equal to 35 of 3,500. Is Cho correct? Explain why.
= Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 37 Monday
Tuesday
1.
10%
of
98
=
1.
10%
of
135
=
2.
50%
of
90
=
2.
50%
of
320
=
3.
25%
of
56
=
3.
25%
of
120
=
4.
20%
of
100
=
4.
20%
of
50
=
5.
23
x
13
=
5.
53
x
23
=
6.
138
÷
6
=
6.
224
÷
7
=
7.
1 56 1 23 7 15 6 15
7.
2 26 2 25 3 5 7 8
x
2
=
+
=
+
4 5 1 3
x
4
=
8. 9. 10.
x
2
+
=
8.
+
2 3 2 5
= =
9.
x
3
=
10.
Wednesday
=
Thursday
1.
10%
of
430
=
1.
10%
of
539
=
2.
50%
of
640
=
2.
50%
of
210
=
3.
25%
of
800
=
3.
25%
of
440
=
4.
20%
of
600
=
4.
20%
of
300
=
5.
44
x
22
=
5.
23
x
34
=
6.
315
÷
7
=
6.
260
÷
4
=
7.
2 26
x
3
=
7.
x
2
=
+
=
8.
+
=
9.
+
2 5 1 3
=
+
5 6 2 3
1 13
x
4
=
10.
x
4
=
8. 9. 10.
1 26 1 6 2 3
Friday 1.
10%
of
109
=
2.
50%
of
520
=
3.
25%
of
60
=
4.
20%
of
240
=
5.
31
x
42
=
6.
375
÷
5
=
7.
1 15 1 26 3 4 1 3
x
3
=
+
=
+
4 6 1 5
x
7
=
8. 9. 10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 115
1 15 1 4 2 5
=
Ninja challenge
Sam adds 14.56 to 7.9 and gets the answer 22.46. Is Sam correct? Explain why.
=
115
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 37 Monday 1.
45.78
2.
Tuesday
+
3.9
=
=
34.6
–
1. 8.78
42.8
2.
+
5.69
=
=
76.35
–
7.8
3.
50%
of
48
=
3.
50%
of
36
=
4.
10%
of
48
=
4.
25%
of
36
=
5.
20%
of
48
=
5.
10%
of
36
=
6.
1x1
=
=
1²
6.
2x2
=
=
2²
7.
1x1x1
=
=
1³
7.
2x2x2
=
=
2³
to
√1
8.
√4
8. 9. 10.
is 1 14 3 14
equal
x
5
=
9.
x
5
=
10.
1 13 1 13
Wednesday 1.
35.56
2.
is
equal
to
x
4
=
x
7
=
Thursday
+
7.9
=
=
87.4
–
1. 9.6
67.6
2.
+
4.76
=
=
34.74
–
4.8
3.
100%
of
15
=
3.
50%
of
80
=
4.
10%
of
15
=
4.
25%
of
80
=
5.
1%
of
15
=
5.
20%
of
80
=
6.
3x3
=
=
3²
6.
4x4
=
=
4²
7.
3x3x3
=
=
3³
7.
4x4x4
=
=
4³
to
√9
8.
√16
8. 9. 10.
is 4 15 4 25
equal
x
6
=
9.
x
6
=
10.
85.45
2.
+
5.8
=
=
65.4
–
8.7
3.
100%
of
24
=
4.
10%
of
24
=
5.
1%
of
24
=
6.
5x5
=
=
5²
7.
5x5x5
=
=
5³ √25
8. 9. 10.
2 35
2 35
is
equal
to
x
2
=
x
3
=
116
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 116
is
equal
to
x
8
=
x
9
=
Ninja challenge
Friday 1.
3 17 3 17
Iko adds 401,384 to 313,394. Iko says that the answer is less than 710,000. Is Iko correct? Explain why.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 37 Monday
Tuesday
1.
=
9
x
1,739
1.
=
7
x
3,261
2.
=
1,896
÷
3
2.
=
9,480
÷
5
3.
=
183,227
+
103,283
3.
=
205,341
+
194,323
4.
=
743,483
–
152,374
4.
=
841,405
–
204,231
–
1.05
=
–
13.73
=
=
27
+
=
45
+
5.
10
6.
5. 13.67
20
6.
7.
10%
of
3,253
=
7.
10%
of
2,319
=
8.
20%
of
1,400
=
8.
20%
of
3,400
=
9.
3 14 3 34
2 15 1 36
x
4
=
–
1 14
=
10.
x
3
=
9.
–
2 25
=
10.
Wednesday
21.04
Thursday
1.
=
8
x
3,556
1.
=
9
x
4,121
2.
=
3,042
÷
6
2.
=
5,841
÷
9
3.
=
313,284
+
211,242
3.
=
577,103
+
136,439
4.
=
751,232
–
546,667
4.
=
506,504
–
299,353
–
21.04
=
–
79.37
=
=
51
+
=
62
+
5.
40
6.
5. 29.04
90
6.
7.
10%
of
3,105
=
7.
10%
of
5,317
=
8.
20%
of
1,900
=
8.
20%
of
2,500
=
9.
3 13 3 46
9.
4 13 4 25
x
2
=
–
9 210
=
10.
x
3
–
2 34
=
10.
=
Friday 1.
=
4
x
5,714
2.
=
3,665
÷
5
3.
=
74,392
+
63,294
4.
=
105,495
–
93,941
–
56.43
=
=
75
+
5.
110
6. 7.
10%
of
6,721
=
8.
20%
of
4,800
=
9.
4 16
x
3
=
–
1 56
=
10.
3 23
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 117
32.32
Ninja challenge
Sam says that 717,758 more than 190,327 equals 908,805. Is Sam correct? Explain why.
26.31
117
15/09/2022 09:59
v
GRASSHOPPER LEVEL
WEEK 38 Monday
Tuesday
1.
10%
of
342
=
1.
10%
of
206
=
2.
10%
of
540
=
2.
10%
of
710
=
3.
143,261
+
35,305
=
3.
230,768
+
67,780
=
4.
50,000
–
13,374
=
4.
70,000
–
25,761
=
5.
26
x
37
=
5.
34
x
42
=
6.
576
÷
9
=
6.
486
÷
9
=
7.
1 24 1 12 3 5 1 6
7.
1 14 2 69 3 10 1 5
x
6
=
+
=
+
7 9 5 15
x
7
=
8. 9. 10.
x
3
+
=
8.
+
1 2 5 15
= =
9.
x
7
=
10.
Wednesday
=
Thursday
1.
10%
of
432
=
1.
10%
of
317
=
2.
10%
of
670
=
2.
10%
of
870
=
3.
321,760
+
56,783
=
3.
412,078
+
54,979
=
4.
90,000
–
34,808
=
4.
120,000
–
97,825
=
5.
42
x
51
=
5.
37
x
25
=
6.
504
÷
8
=
6.
444
÷
6
=
7.
1 13
x
5
=
7.
x
5
=
+
=
8.
+
=
9.
+
6 9 4 10
=
+
3 9 5 14
2 19
x
5
=
10.
x
10
=
8. 9. 10.
2 19 1 2 2 6
Friday 1.
10%
of
907
=
2.
10%
of
470
=
3.
504,608
+
67,827
=
4.
150,000
–
87,809
=
5.
38
x
26
=
6.
522
÷
6
=
7.
1 18 1 110 2 3 2 5
x
2
=
+
=
+
6 10 4 18
x
12
=
8. 9. 10. 118
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 118
3 19 2 5 2 6
=
Ninja challenge
Iko subtracts 22.3 from 34.53 and gets an answer of 12.5. Is Iko correct?
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
SHINOBI LEVEL
WEEK 38 Monday
Tuesday
1.
55.67
+
2.
43.91
=
52.7
–
2.
22.86
=
3.
100%
of
35
=
3.
50%
of
50
=
4.
10%
of
35
=
4.
25%
of
50
=
5.
1%
of
35
=
5.
20%
of
50
=
6.
6x6
=
=
6²
6.
7x7
=
=
7²
7.
6x6x6
=
=
6³
7.
7x7x7
=
=
7³
to
√36
8.
√49
8. 9. 10.
is 2 37 2 37
=
equal
62.47
1.
x
3
=
9.
x
4
=
10.
+
3 47 3 47
Wednesday
7.97
=
53.57
–
9.7
is
equal
to
x
3
=
x
4
=
Thursday
1.
34.67
+
2.
37.33
=
45.3
–
2.
66.95
=
3.
100%
of
16
=
3.
50%
of
90
=
4.
10%
of
16
=
4.
25%
of
90
=
5.
1%
of
16
=
5.
20%
of
90
=
6.
8x8
=
=
8²
6.
9x9
=
=
9²
7.
8x8x8
=
=
8³
7.
9x9x9
=
=
9³
to
√64
8.
√81
8. 9. 10.
is 3 45 3 45
=
equal
42.47
x
2
=
9.
x
3
=
10.
Friday 1.
67.89
+
2.
66.76
=
75.4
–
3.
100%
of
8
=
4.
10%
of
8
=
5.
1%
of
8
=
6.
10 x 10
=
=
10²
7.
10 x 10 x 10
=
=
10³ √100
8. 9. 10.
7 210
9 210
1.
=
is
equal
to
x
3
=
x
3
=
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 119
74.49
+
2 49 2 49
7.86
=
34.46
–
8.7
is
equal
to
x
3
=
x
4
=
Ninja challenge
Iko stated that the total of 4,000 lots of 8 is equal to 12,000. Is she correct? Explain why.
119
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 38 Monday
Tuesday
1.
=
10%
of
367
1.
=
10%
of
713
2.
x
1,000
=
560
2.
x
1,000
=
430
3.
0.09
=
÷
100
3.
0.01
=
÷
100
4.
1%
of
=
17.5
4.
1%
of
=
23.7
5.
7,000
x
100
=
5.
5,000
x
100
=
6.
x
5
=
21,525
6.
x
5
=
18,510
7.
=
32
x
74
7.
=
37
x
64
8.
÷
6
=
129
8.
÷
7
=
215
9.
=
5,139
÷
9
9.
=
5,562
÷
9
10.
=
360,000
÷
6
10.
=
270,000
÷
3
Wednesday
Thursday
1.
=
10%
of
804
1.
=
10%
of
919
2.
x
1,000
=
170
2.
x
1,000
=
1,050
3.
0.07
=
÷
100
3.
0.05
=
÷
100
4.
1%
of
=
19.3
4.
1%
of
=
94.5
5.
4,000
x
40
=
5.
6,000
x
70
=
6.
x
7
=
12,110
6.
x
6
=
14,160
7.
=
52
x
73
7.
=
77
x
81
8.
÷
8
=
285
8.
÷
9
=
375
9.
=
6,552
÷
9
9.
=
3,965
÷
5
10.
=
320,000
÷
4
10.
=
640,000
÷
8
Friday 1.
=
10%
of
1,056
2.
x
1,000
=
60
3.
0.08
=
÷
100
4.
1%
of
=
71.3
5.
8,000
x
40
=
6.
x
9
=
66,438
7.
=
83
x
87
8.
÷
6
=
746
9.
=
5,978
÷
7
10.
=
720,000
÷
9
120
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 120
Ninja challenge
Tom multiplies the product of 70 times 90 by 3. What answer does Tom have?
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRASSHOPPER LEVEL
WEEK 39 Monday
Tuesday
1.
10%
of
3
=
1.
10%
of
14
=
2.
10%
of
48
=
2.
10%
of
160
=
3.
34.1
+
13.45
=
3.
42.1
+
5.46
=
4.
27
–
12.23
=
4.
13
–
9.05
=
5.
36
x
34
=
5.
37
x
17
=
6.
435
÷
5
=
6.
576
÷
6
=
7.
1 14 2 210 2 5 2 4
7.
1 13 2 110 2 4 2 5
x
7
=
+
=
+
7 10 2 5
x
9
=
8. 9. 10.
x
6
+
=
8.
+
5 10 1 2
= =
9.
x
9
=
10.
Wednesday
=
Thursday
1.
10%
of
72
=
1.
10%
of
98
=
2.
10%
of
200
=
2.
10%
of
350
=
3.
56.1
+
5.69
=
3.
34.5
+
3.49
=
4.
21
–
11.4
=
4.
19
–
15.7
=
5.
42
x
22
=
5.
35
x
26
=
6.
728
÷
7
=
6.
992
÷
8
=
7.
1 18
x
4
=
7.
x
5
=
+
=
8.
+
=
9.
+
5 6 8 20
=
+
2 3 2 5
1 14
x
5
=
10.
x
3
=
8. 9. 10.
3 23 4 10 4 11
Friday 1.
10%
of
104
=
2.
10%
of
560
=
3.
57.3
+
5.41
=
4.
30
–
17.4
=
5.
45
x
19
=
6.
981
÷
9
=
7.
2 13 1 45 3 5 5 6
x
5
=
+
=
+
2 5 5 20
x
3
=
8. 9. 10.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 121
2 26 5 10 4 9
=
Ninja challenge
Tom says that the answer to 9,000 x 2 is 3,000 more than 16,000. Is Tom correct? Explain why.
=
121
15/09/2022 09:59
v
SHINOBI LEVEL
WEEK 39 Monday 1.
–
7.86
Tuesday =
48.54
1.
65.68
–
+
9.6
2.
58.47
=
54.8
+
=
57.78
2.
45.39
=
3.
100%
of
11
=
3.
50%
of
400
=
4.
10%
of
11
=
4.
20%
of
400
=
5.
1%
of
11
=
5.
25%
of
400
=
6.
11 x 11
=
=
11²
6.
12 x 12
=
=
12²
7.
11 x 11 x 11
=
=
11³
7.
12 x 12 x 12
=
=
12³
to
√121
8.
√144
8. 9. 10.
is 5 211 5 211
equal
x
4
=
9.
x
5
=
10.
2 38 2 78
Wednesday 1.
–
8.9
is
equal
to
x
11
=
x
11
=
Thursday =
38.5
1.
86.57
–
+
7.9
2.
66.95
=
57.2
+
=
2.
73.2
=
3.
100%
of
4
=
3.
50%
of
600
=
4.
10%
of
4
=
4.
25%
of
600
=
5.
1%
of
4
=
5.
20%
of
600
=
6.
5²
is
equal
to
6.
7²
is
equal
to
7.
6³
is
equal
to
7.
11³
is
equal
to
is
equal
to
is
equal
to
x
6
=
x
7
=
8. 9. 10.
1 38 1 38
√64
x
6
=
9.
x
7
=
10.
Friday 1.
–
8.67
=
65.63
+
7.6
2.
76.34
=
3.
100%
of
134
=
4.
10%
of
134
=
5.
1%
of
134
=
6.
8²
is
equal
to
7.
4³
is
equal
to
is
equal
to
x
7
=
x
7
=
8. 9. 10.
1 113 7 113
8.
122
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 122
1 35 1 35
79.17
√9
Ninja challenge
Cho divides 640 by 100. She says the answer is equal to 1.6 less than 8. Is Cho correct? Explain why.
√81
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
GRAND MASTER LEVEL
WEEK 39 Monday
Tuesday
1.
=
20%
of
160
1.
=
20%
of
450
2.
x
100
=
6
2.
x
100
=
7
3.
=
8,430
÷
1,000
3.
=
6,470
÷
1,000
4.
1%
of
640
=
4.
1%
of
510
=
5.
800
x
40
=
5.
700
x
30
=
6.
x
7
=
35,343
6.
x
4
=
32,152
7.
=
153
x
54
7.
=
252
x
67
8.
÷
7
=
556
8.
÷
3
=
639
9.
=
1,896
÷
3
9.
=
2,847
÷
3
10.
=
72,000
÷
9
10.
=
18,000
÷
3
Wednesday
Thursday
1.
=
20%
of
670
1.
=
20%
of
810
2.
x
100
=
84
2.
x
100
=
92
3.
=
5,005
÷
1,000
3.
=
7,380
÷
1,000
4.
1%
of
680
=
4.
1%
of
125
=
5.
500
x
60
=
5.
300
x
60
=
6.
x
4
=
29,096
6.
x
4
=
32,924
7.
=
363
x
56
7.
=
417
x
62
8.
÷
3
=
949
8.
÷
5
=
912
9.
=
4,719
÷
3
9.
=
7,611
÷
3
10.
=
35,000
÷
7
10.
=
45,000
÷
5
Friday 1.
=
20%
of
920
2.
x
100
=
17
3.
=
8,310
÷
1,000
4.
1%
of
324
=
5.
900
x
60
=
6.
x
4
=
36,172
7.
=
532
x
73
8.
÷
5
=
683
9.
=
10,599
÷
3
10.
=
96,000
÷
12
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 123
Ninja challenge
Iko tells Sam that 63,000 is equal to 89 of 72,000. Is Iko correct? Explain why.
123
15/09/2022 09:59
ANSWERS Week 1: Week 1: Grasshopper Shinobi Monday Monday
Week 1: Week 2: Week 2: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 2: Week 3: Week 3: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 3: Grand Master Monday
1. 4,204 2. 2,222 3. 3.7 4. 947 5. 4,440 6. 1.2 7. 40 8. 63 9. 9 10. 8
1. 7,433 2. 7,523 3. 8,423 4. 0.55 5. 0.77 6. 500 7. 10 8. 12 9. 12 10. 120
1. 37.2 2. 7.8 3. 360 4. 9 5. 1,315 6. 57 7. 4.3 8. 80,891 9. 32,904 10. 59
1. 12,059 2. 7,880 3. 1.5 4. 9,593 5. 3,225 6. 5.3 7. 24 8. 240 9. 6 10. 60
1. 34,503 2. 34,593 3. 35,493 4. 0.44 5. 0.95 6. 38,564 7. 590 8. 72 9. 72 10. 720
1. 46.2 2. 24.8 3. 3,600 4. 60 5. 2,105 6. 810 7. 4,100 8. 66,134 9. 29,809 3 10. 13
1. 15,774 2. 13.2 3. 5,151 4. 3.6 5. 42 6. 180 7. 9 8. 40 9. 56 10. 9
1. 67,039 2. 66,949 3. 66,049 4. 0.47 5. 0.11 6. 53,647 7. 3,069 8. 24 9. 24 10. 240
1. 45,595 2. 3.62 3. 0.95 4. 0.17 5. 328,485 6. 0.83 7. 230,759 8. 4,998 9. 938,012 10. 13
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 5,004 2. 3,647 3. 4.9 4. 969 5. 3,508 6. 1.6 7. 42 8. 45 9. 4 10. 4
1. 5,707 2. 5,797 3. 6,697 4. 0.03 5. 0.78 6. 3,676 7. 85 8. 24 9. 24 10. 240
1. 52.2 2. 11.8 3. 350 4. 9 5. 1,122 6. 64 7. 8.7 8. 70,483 9. 38,585 10. 59
1. 13,477 2. 10,364 3. 2.3 4. 10,622 5. 5113 6. 5.8 7. 28 8. 300 9. 9 10. 110
1. 48,957 2. 49,047 3. 49,947 4. 0.96 5. 0.32 6. 34,966 7. 9,500 8. 35 9. 35 10. 350
1. 5.6 2. 30.7 3. 4,500 4. 40 5. 1,056 6. 430 7. 3,500 8. 81,187 9. 38,894 9 10. 13
1. 15,623 2. 10.3 3. 4,173 4. 3.6 5. 36 6. 630 7. 6 8. 120 9. 46 10. 12
1. 36,485 2. 36,395 3. 35,495 4. 0.96 5. 0.66 6. 24,566 7. 70,005 8. 32 9. 32 10. 320
1. 66,428 2. 7.52 3. 0.97 4. 0.23 5. 402,104 6. 0.93 7. 348,006 8. 5,818 9. 103,485 10. 18
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 1,112 2. 4,609 3. 7.1 4. 1,739 5. 2,373 6. 2.3 7. 24 8. 36 9. 4 10. 5
1. 2,495 2. 2,585 3. 3,485 4. 0.33 5. 0.13 6. 3,368 7. 690 8. 18 9. 18 10. 180
1. 68.1 2. 19.7 3. 420 4. 6 5. 1,648 6. 56 7. 9.2 8. 97,472 9. 32,089 10. 18
1. 13,522 2. 8,934 3. 7.1 4. 5,239 5. 4,110 6. 7.5 7. 12 8. 420 9. 3 10. 90
1. 67,339 2. 67,429 3. 68,329 4. 0.18 5. 0.09 6. 82,556 7. 3,404 8. 16 9. 16 10. 160
1. 15.1 2. 32.5 3. 2,100 4. 70 5. 3,075 6. 620 7. 2,900 8. 58,263 9. 66,979 9 10. 14
1. 15,466 2. 14.9 3. 3,260 4. 2.8 5. 54 6. 360 7. 9 8. 80 9. 56 10. 9
1. 67,482 2. 67,392 3. 66,492 4. 0.41 5. 0.77 6. 56,359 7. 8,093 8. 56 9. 56 10. 560
1. 70,748 2. 10.19 3. 0.92 4. 0.54 5. 285,384 6. 0.73 7. 404,589 8. 3,998 9. 122,374 10. 13
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 1,045 2. 4,746 3. 10.2 4. 2,284 5. 2,207 6. 4.4 7. 45 8. 64 9. 6 10. 8
1. 6,807 2. 6,897 3. 7,897 4. 0.49 5. 0.01 6. 9,844 7. 94 8. 66 9. 66 10. 660
1. 88.1 2. 14.6 3. 540 4. 4 5. 1,644 6. 94 7. 8.2 8. 107,192 9. 51,242 3 10. 12
1. 14,992 2. 8,667 3. 7.2 4. 6,624 5. 3,108 6. 2.9 7. 40 8. 280 9. 8 10. 80
1. 56,492 2. 56,582 3. 57,482 4. 0.64 5. 0.31 6. 78,524 7. 4,506 8. 8 9. 8 10. 80
1. 19.3 2. 12 3. 6,400 4. 90 5. 2,075 6. 710 7. 8,300 8. 91,610 9. 57,799 4 10. 14
1. 14,569 2. 13.8 3. 6,143 4. 6.5 5. 28 6. 720 7. 8 8. 70 9. 67 10. 20
1. 78,584 2. 78,494 3. 77,594 4. 0.56 5. 0.77 6. 95,634 7. 4,504 8. 36 9. 36 10. 360
1. 95,859 2. 12.46 3. 0.86 4. 0.59 5. 702,481 6. 0.97 7. 205,837 8. 5,100 9. 122,374 10. 34
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 2,015 2. 6,695 3. 9.7 4. 3,371 5. 4,225 6. 4.6 7. 40 8. 54 9. 5 10. 7
1. 2,492 2. 2,582 3. 3,482 4. 0.99 5. 0.88 6. 9,945 7. 680 8. 30 9. 30 10. 300
1. 105.5 2. 28.3 3. 630 4. 12 5. 2,289 6. 81 7. 9.3 8. 109,989 9. 37,627 3 10. 13
1. 15,710 2. 10,605 3. 9.2 4. 9,581 5. 4,641 6. 3.5 7. 56 8. 210 9. 4 10. 60
1. 42,606 2. 42,696 3. 43,596 4. 0.93 5. 0.89 6. 93,436 7. 7,290 8. 45 9. 45 10. 450
1. 45.9 2. 12.2 3. 7,200 4. 120 5. 4,338 6. 850 7. 1,100 8. 141,678 9. 20,812 10. 11 15
1. 17,782 2. 11.7 3. 4,211 4. 5.7 5. 25 6. 350 7. 3 8. 120 9. 57 10. 21
1. 30,395 2. 30,305 3. 29,404 4. 0.87 5. 0.97 6. 74,453 7. 9,080 8. 55 9. 55 10. 550
1. 85,862 2. 11.76 3. 0.58 4. 0.02 5. 523,495 6. 1.27 7. 109,758 8. 4,408 9. 248,019 10. 41
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
2630
Yes, 3 x 40 = 120.
No, 29,236 + No, he has 240 9,362 = 38,598. counters, 4 x 60 = 240.
Yes, half of 2,000 is 1,000 and double 500 is 1,000.
313,392
120
3
No, 700 x 9 = 6,300 and 600 x 11= 6,600.
124
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 124
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
ANSWERS Week 4: Week 4: Grasshopper Shinobi Monday Monday
Week 4: Week 5: Week 5: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 5: Week 6: Week 6: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 6: Grand Master Monday
1. 13,641 2. 0.75 3. 2,915 4. 0.63 5. 25 6. 1,800 7. 4 8. 50 9. 27 10. 49
1. 80,493 2. 80,403 3. 79,503 4. 0.86 5. 0.55 6. 86,695 7. 190 8. 72 9. 720 10. 7,200
1. 85,862 2. 21.76 3. 2.62 4. 1.02 5. 203,485 6. 12.76 7. 210,843 8. 15,806 9. 53,040 10. 29
1. 12,377 2. 14,373 3. 7,791 4. 13,274 5. 28 6. 4,200 7. 8 8. 80 9. 15 19 10. 15
1. 495,604 2. 495,594 3. 494,594 4. 0.44 5. 0.68 6. 4,080 7. 45,090 8. 270 9. 2,700 10. 27,000
1. 6,809 2. 6.03 3. 7.1 4. 6.6 5. 126,481 6. 5.4 7. 83,495 8. 9,584 9. 51,384 10. 5
1. 1.23 2. 0.96 3. 30 4. 129 5. 56 6. 2,000 7. 8 8. 40 9. 97 or 1 27 10. 6
1. 134,959 2. 135,069 3. 135,969 4. 0.658 5. 0.991 6. 30,055 7. 2,059 8. 420 9. 4,200 10. 42,000
1. 23,275 2. 14.17 3. 4.6 4. 8.4 5. 153,635 6. 5.7 7. 26,232 8. 4,000 9. 76,976 10. 39
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 15,955 2. 0.72 3. 3,663 4. 0.65 5. 28 6. 2,800 7. 4 8. 80 9. 18 10. 28
1. 67,944 2. 67,854 3. 66,954 4. 0.38 5. 0.92 6. 98,465 7. 1,390 8. 56 9. 560 10. 5,600
1. 97,879 2. 22.6 3. 5.71 4. 1.64 5. 317,273 6. 15.53 7. 205,136 8. 37,501 9. 17,273 10. 25
1. 13,271 2. 13,303 3. 3,395 4. 19,304 5. 48 6. 4,500 7. 4 8. 50 9. 15 19 10. 54
1. 275,339 2. 275,449 3. 276,349 4. 0.77 5. 0.09 6. 79,233 7. 23,454 8. 180 9. 1,800 10. 18,000
1. 14,460 2. 2.85 3. 3.7 4. 4.7 5. 132,384 6. 4.9 7. 45,612 8. 7,381 9. 43,281 10. 12
1. 1.2 2. 0.59 3. 60 4. 208 5. 24 6. 4,200 7. 4 8. 60 9. 87 or 1 17 10. 18
1. 729,194 2. 729,084 3. 728,194 4. 0.258 5. 0.979 6. 40,806 7. 590 8. 240 9. 2,400 10. 24,000
1. 23,382 2. 17.02 3. 5.8 4. 24.1 5. 172,887 6. 6.8 7. 42,335 8. 7,000 9. 65,089 10. 117
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 15,748 2. 0.79 3. 2,205 4. 0.48 5. 27 6. 2,100 7. 6 8. 80 9. 49 10. 40
1. 12,029 2. 11,939 3. 11,039 4. 0.44 5. 0.68 6. 23,495 7. 7,390 8. 63 9. 630 10. 6,300
1. 109,696 2. 25.21 3. 6.47 4. 2.14 5. 219,294 6. 21.53 7. 218,664 8. 63,132 9. 15,553 10. 50
1. 15,051 2. 9,184 3. 2,385 4. 9,803 5. 40 6. 1,800 7. 8 8. 120 9. 16 19 10. 24
1. 855,600 2. 855,490 3. 854,590 4. 0.95 5. 0.17 6. 5,860 7. 3,040 8. 560 9. 5,600 10. 56,000
1. 30,800 2. 6.12 3. 6.1 4. 2.7 5. 203,405 6. 7.4 7. 56,704 8. 8,405 9. 51,285 10. 40
1. 1.42 2. 0.45 3. 130 4. 162 5. 48 6. 3,500 7. 7 8. 30 3 9. 12 9 or 1 9 10. 14
1. 183,493 2. 183,403 3. 184,503 4. 0.497 5. 0.639 6. 1,056 7. 940,500 8. 560 9. 5,600 10. 56,000
1. 34,976 2. 20.85 3. 6.2 4. 63.3 5. 145,087 6. 0.8 7. 20,195 8. 8,000 9. 56,111 10. 36
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 17,684 2. 0.89 3. 5775 4. 0.24 5. 72 6. 4,200 7. 11 8. 90 2 9. 10 10. 45
1. 596,483 2. 596,393 3. 595,493 4. 0.45 5. 0.06 6. 576,595 7. 90,094 8. 96 9. 960 10. 9,600
1. 78,901 2. 27.85 3. 9.91 4. 3.67 5. 435,502 6. 24.71 7. 237,787 8. 65,408 9. 32,183 10. 45
1. 8,013 2. 12,032 3. 3,719 4. 8,945 5. 56 6. 2,700 7. 11 8. 60 9. 20 21 10. 30
1. 365,485 2. 365,595 3. 366,495 4. 0.93 5. 0.55 6. 90,098 7. 95 8. 220 9. 2,200 10. 22,000
1. 34,082 2. 6.92 3. 2.1 4. 1.5 5. 160,947 6. 8.5 7. 70,374 8. 5,405 9. 51,285 10. 45
1. 1.1 2. 0.36 3. 240 4. 245 5. 64 6. 2,800 7. 12 8. 110 5 9. 14 9 or 1 9 10. 72
1. 924,107 2. 924,197 3. 923,097 4. 0.407 5. 0.974 6. 31,003 7. 780,500 8. 660 9. 6,600 10. 66,000
1. 44,986 2. 17.95 3. 7.5 4. 57.5 5. 151,888 6. 5.1 7. 26,935 8. 9,000 9. 43,809 10. 17
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 15,641 2. 0.66 3. 6,380 4. 0.28 5. 63 6. 2,000 7. 9 8. 60 1 9. 10 10. 18
1. 875,099 2. 875,009 3. 874,109 4. 0.23 5. 0.39 6. 204,193 7. 17,003 8. 27 9. 270 10. 2,700
1. 37,599 2. 32.79 3. 15.93 4. 4.12 5. 126,491 6. 21.25 7. 286,677 8. 59,609 9. 52,045 10. 41
1. 9,122 2. 8,484 3. 10,833 4. 25,371 5. 72 6. 5,400 7. 9 8. 90 9. 16 21 10. 54
1. 845,604 2. 845,494 3. 844,594 4. 0.89 5. 0.92 6. 30,059 7. 2,005 8. 240 9. 2,400 10. 24,000
1. 42,103 2. 10.45 3. 3.5 4. 8.4 5. 194,380 6. 4.6 7. 64,311 8. 4,311 9. 64,781 10. 33
1. 1.78 2. 0.59 3. 310 4. 344 5. 16 6. 3,600 7. 12 8. 80 7 9. 17 10 or 1 10 10. 18
1. 282,995 2. 282,905 3. 284,005 4. 0.615 5. 0.948 6. 20,052 7. 5,204 8. 960 9. 9,600 10. 96,000
1. 53,044 2. 4.77 3. 7.8 4. 65.7 5. 165,856 6. 8.5 7. 37,435 8. 9,000 9. 17,535 10. 27
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
344
7,601
No, 10,000 less No, the answer No, 7 x 80 = than 133,743 is is 2,230. 560. 123,743.
No, 4 groups of No, 10 less Yes, 6 x 871= 70 = 280. than 1,904, is 5,226. 1894, which is less than 1,905.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 125
80
125
15/09/2022 09:59
ANSWERS
1 2
Week 7: Week 7: Grasshopper Shinobi Monday Monday
Week 7: Week 8: Week 8: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 8: Week 9: Week 9: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 9: Grand Master Monday
1. 2.12 2. 0.7 3. 79,654 4. 258 5. 429 6. 36 7. 12 8. 40 3 9. 17 14 or 1 14 10. 12
1. 61,080 2. 9.11 3. 31,557 4. 25.79 5. 124 6. 35 7. 370 8. 0.45 9. 54 or 1 14 7 10. 14 20 or 10
1. 10.59 2. 4.14 3. 2,593 4. 80 5. 45 6. 5,460 7. 0.46 8. 0.05 9. 3.2 10. 63
1. 13,273 2. 20.01 3. 14,325 4. 58.32 5. 144 6. 87 7. 26 8. 0.06 9. 59 10. 48 or 12
1. 635 2. 1,255 3. 0.6 4. 8.1 5. 6 6. 630 7. 0.86 8. 5.5 9. 0.73 10. 27
1. 295,493 2. 205,493 3. 121 4. 121 5. 121 6. 11 7. 8,910 8. 11,880 9. 89 10. 49
1. 3.02 2. 46 3. 0.81 4. 56 5. 258 6. 6,710 7. 490 8. 80 9. 49 10. 46 or 23
1. 596,493 2. 686,493 3. 1 4. 1 5. 1 6. 712 7. 1,068 8. 1,780 9. 75 or 1 25 10. 95 or 1 45
1. 496,604 2. 586,604 3. 36 4. 36 5. 6 6. 686 7. 1,029 8. 1,715 3 9. 12 9 or 1 9 15 10. 9 or 1 69
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 1.8 2. 1.5 3. 74,424 4. 145 5. 964 6. 48 7. 6 8. 90 3 9. 18 15 or 1 15 10. 20
1. 848,034 2. 938,034 3. 4 4. 4 5. 4 6. 1,676 7. 2,514 8. 4,190 9. 98 or 1 18 4 10. 12 8 or 1 8
1. 52,929 2. 17.98 3. 38,944 4. 24.2 5. 174 6. 45 7. 240 8. 0.17 9. 86 or 1 26 10. 13 15
1. 11.78 2. 3.62 3. 7,980 4. 20 5. 12 6. 2,060 7. 0.19 8. 0.06 9. 5.6 10. 18
1. 294,392 2. 384,392 3. 49 4. 49 5. 7 6. 4,648 7. 6,972 8. 11,620 2 9. 17 15 or 1 15 4 10. 19 or 1 15 5
1. 10,273 2. 29.27 3. 13,603 4. 61.81 5. 247 6. 92 7. 54 8. 0.09 9. 69 5 10. 12
1. 64 2. 1,583 3. 0.9 4. 3.2 5. 5 6. 870 7. 0.17 8. 4.3 9. 0.61 10. 18
1. 824,392 2. 734,392 3. 144 4. 144 5. 144 6. 12 7. 44,307 8. 19,692 9. 11 13 2 10. 15 13 or 1 13
1. 4.13 2. 61 3. 0.74 4. 13 5. 268 6. 7,635 7. 300 8. 80 9. 79 10. 11 15
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 1.77 2. 1.22 3. 44,461 4. 324 5. 1,078 6. 42 7. 12 8. 90 8 9. 23 15 or 1 15 10. 35
1. 609,492 2. 699,492 3. 9 4. 9 5. 9 6. 2,586 7. 3,879 8. 6,465 3 9. 12 9 or 1 9 1 10. 10 or 1 9 9
1. 40,833 2. 24.55 3. 50,788 4. 25.76 5. 156 6. 65 7. 470 8. 0.23 4 9. 10 6 or 1 6 10. 11 12
1. 13.48 2. 3.18 3. 22,124 4. 10 5. 78 6. 3,140 7. 0.41 8. 0.09 9. 2.9 10. 18
1. 467,764 2. 557,764 3. 64 4. 64 5. 8 6. 3,354 7. 5,301 8. 8,835 1 9. 20 19 or 1 19 7 10. 26 or 1 19 19
1. 14,384 2. 25.24 3. 15,112 4. 66.19 5. 217 6. 82 7. 87 8. 0.14 9. 49 6 3 10. 20 or 10
1. 787 2. 1,126 3. 1.7 4. 5.7 5. 9 6. 910 7. 0.89 8. 7.8 9. 0.92 10. 14
1. 485,592 2. 395,592 3. 100 4. 100 5. 100 6. 10 7. 20,958 8. 13,972 1 9. 21 20 or 1 20 10. 13 20
1. 5.06 2. 23 3. 0.15 4. 45 5. 287 6. 8,495 7. 630 8. 70 9. 46 or 23 7 10. 10
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 2.23 2. 0.79 3. 54,411 4. 322 5. 2,600 6. 30 7. 12 8. 20 13 9. 28 15 or 1 15 10. 9
1. 219,493 2. 309,493 3. 16 4. 16 5. 16 6. 6,984 7. 10,476 8. 17,460 4 9. 15 11 or 1 11 8 10. 19 or 1 11 11
1. 42,623 2. 23.22 3. 51,430 4. 25.32 5. 135 6. 71 7. 560 8. 0.28 9. 87 or 1 17 5 10. 10 12 or 6
1. 14.2 2. 5.05 3. 12,818 4. 30 5. 61 6. 2,870 7. 0.94 8. 0.06 9. 4.8 10. 30
1. 202,394 2. 292,394 3. 81 4. 81 5. 9 6. 9,314 7. 13,971 8. 23,285 4 9. 24 20 or 1 20 7 10. 27 or 1 20 20
1. 16,477 2. 31.21 3. 15,607 4. 61.3 5. 197 6. 67 7. 96 8. 0.23 9. 39 4 10. 10 or 25
1. 499 2. 1,519 3. 1.1 4. 7.9 5. 4 6. 830 7. 0.73 8. 4.6 9. 0.86 10. 48
1. 374,593 2. 284,593 3. 81 4. 81 5. 81 6. 9 7. 34,792 8. 26,094 1 9. 14 13 or 1 13 10. 11 13
1. 4.82 2. 56 3. 0.85 4. 27 5. 277 6. 6,288 7. 480 8. 50 9. 46 or 23 8 10. 10 or 45
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 2.59 2. 1.42 3. 51,709 4. 504 5. 3,717 6. 72 7. 4 8. 80 5 9. 26 21 or 1 21 10. 72
1. 255,392 2. 345,392 3. 25 4. 25 5. 25 6. 4,990 7. 7,485 8. 12,475 9. 13 13 or 1 7 10. 20 13 or 1 13
1. 25,854 2. 22.89 3. 42,942 4. 31.45 5. 122 6. 75 7. 750 8. 0.71 3 9. 10 7 or 1 7 10. 78
1. 18.05 2. 9 3. 7,071 4. 80 5. 51 6. 6,230 7. 0.86 8. 0.05 9. 7.3 10. 18
1. 463,394 2. 553,394 3. 100 4. 100 5. 10 6. 4,970 7. 7,455 8. 12,425 7 9. 30 23 or 1 23 14 10. 37 23 or 1 23
1. 18,823 2. 36.54 3. 16,712 4. 65.55 5. 235 6. 39 7. 49 8. 0.51 9. 89 2 10. 15
1. 176 2. 1,806 3. 2.6 4. 5.6 5. 3 6. 670 7. 0.14 8. 1.2 9. 0.17 10. 16
1. 309,302 2. 219,302 3. 64 4. 64 5. 64 6. 8 7. 9,968 8. 14,952 3 9. 14 11 or 1 11 1 10. 12 11 or 1 11
1. 3.19 2. 76 3. 0.61 4. 33 5. 302 6. 6,714 7. 420 8. 70 9. 27 7 10. 20
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
1,136
No, 60,002 – 400,003 1,000 = 59,002.
16,891
Iko, 210 x 2 = 420, half 830 is 415.
No, the difference is 8,546.
2,250
126
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 126
No, 1,200 less than 2,700 is 1,500.
Yes, both are equal to 10,000.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
ANSWERS Week 10: Week 10: Grasshopper Shinobi Monday Monday
Week 10: Week 11: Week 11: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 11: Week 12: Week 12: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 12: Grand Master Monday
1. 4,636 2. 1,810 3. 2.3 4. 2,400 5. 12,300 6. 676 7. 145.2 8. 73.6 9. 15 10. 10
1. 457,593 2. 358,593 3. 81 4. 81 5. 81 6. 9 7. 9,576 8. 14,364 9 9. 11 8 10. 11
1. 315 2. 7.6 3. 6.6 4. 39.42 5. 276 6. 8,442 7. 70 8. 90 9. 25 10. 58
1. 4,161 2. 626 3. 2.68 4. 2,700 5. 65,000 6. 660 7. 6.5 8. 0.45 9. 123 10. 20
1. 294,493 2. 564,304 3. 1 4. 4 5. 9 6. 4 7. 17,465 8. 22,455 9. 59 10. 18 9 or 2
1. 45,412 2. 12,400 3. 0.17 4. 184.29 5. 120 6. 56,000 7. 63 or 2 5 8. 15 or 13 9. 231 10. 13,185
1. 6,521 2. 2,979 3. 5.68 4. 530 5. 4,900 6. 83 7. 64 8. 9.2 9. 6,720 10. 42,733
1. 687,493 2. 224,592 3. 6 4. 49 5. 64 6. 9 7. 15,728 8. 35,388 3 9. 25 11 or 2 11 38 10. 39
1. 146.84 2. 67.5 3. 92 4. 3,804 5. 270 6. 560 4 7. 11 7 or 1 7 11 8. 14 9. 240 10. 100
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 4,062 2. 1,750 3. 2.9 4. 4,100 5. 20,300 6. 125 7. 157.3 8. 17.3 9. 24 10. 36
1. 129,403 2. 39,403 3. 64 4. 64 5. 64 6. 8 7. 35,144 8. 26,358 7 9. 14 18 or 9 10. 17 18
1. 283 2. 5.1 3. 5.2 4. 20.34 5. 285 6. 7,483 7. 80 8. 90 9. 34 4 10. 16 20 or 5
1. 4,527 2. 1,630 3. 1.79 4. 5,300 5. 12,000 6. 190 7. 3.5 8. 0.27 9. 172 10. 12
1. 764,493 2. 584,294 3. 2 4. 9 5. 16 6. 5 7. 11,160 8. 9,765 8 9. 10 or 45 8 10. 18 10 or 1 10
1. 17,274 2. 17,900 3. 0.24 4. 174.45 5. 80 6. 21,000 6 7. 13 7 or 1 7 8. 11 20 9. 325 10. 13,527
1. 4,727 2. 6,296 3. 3.59 4. 140 5. 2,300 6. 96 7. 75 8. 8.3 9. 1,240 10. 45,556
1. 853,596 2. 342,405 3. 7 4. 64 5. 81 6. 10 7. 6,025 8. 8,435 6 9. 18 12 or 1 12 4 10. 34 or 1 30 30
1. 253.71 2. 17.4 3. 71 4. 2,304 5. 420 6. 720 5 7. 12 7 or 1 7 8. 13 14 9. 360 10. 200
Wednesday 1. 3,477 2. 1,687 3. 2.8 4. 2,600 5. 41,300 6. 105 7. 240.6 8. 24.5 9. 36 10. 36
Wednesday 1. 443,595 2. 353,595 3. 49 4. 49 5. 49 6. 7 7. 13,980 8. 20,970 6 9. 27 21 or 1 21 10. 20 21
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 183 2. 6.7 3. 8.3 4. 19.05 5. 291 6. 7,623 7. 60 8. 70 9. 39 or 13 10. 17 20
1. 827 2. 3,963 3. 2.84 4. 4,900 5. 37,000 6. 420 7. 6.7 8. 0.92 9. 235 10. 45
1. 864,964 2. 334,329 3. 3 4. 16 5. 25 6. 6 7. 52,902 8. 35,268 6 9. 13 7 or 1 7 7 10. 27 or 1 20 20
1. 23,337 2. 34,500 3. 0.67 4. 345.06 5. 80 6. 35,000 7. 10 5 or 2 5 8. 12 9. 326 10. 14,202
1. 3,740 2. 3,720 3. 3.62 4. 510 5. 1,900 6. 74 7. 32 8. 2.3 9. 1,970 10. 37,050
1. 875,309 2. 792,493 3. 8 4. 81 5. 100 6. 11 7. 31,455 8. 24,465 8 9. 31 23 or 1 23 10. 27 30
1. 323.61 2. 23.9 3. 41 4. 4,329 5. 400 6. 450 5 7. 12 7 or 1 7 8. 15 16 9. 360 10. 80
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 3,695 2. 2,063 3. 3.5 4. 3,300 5. 51,200 6. 167 7. 128.4 8. 32.3 9. 17 10. 84
1. 895,594 2. 805,594 3. 36 4. 36 5. 36 6. 6 7. 17,658 8. 23,544 2 9. 11 9 or 1 9 2 10. 11 or 1 9 9
1. 782 2. 5.6 3. 1.9 4. 20.41 5. 304 6. 7,896 7. 60 8. 70 9. 79 7 10. 10
1. 6,528 2. 1,418 3. 0.91 4. 6,100 5. 19,000 6. 710 7. 5.9 8. 0.83 9. 456 10. 84
1. 879,075 2. 397,546 3. 4 4. 25 5. 36 6. 7 7. 34,146 8. 24,390 3 9. 20 17 or 1 17 6 10. 22 or 1 16 16
1. 36,406 2. 56,300 3. 0.81 4. 219.38 5. 70 6. 49,000 1 7. 15 7 or 2 7 8. 16 9. 341 10. 14,436
1. 1,630 2. 3,830 3. 6.02 4. 760 5. 1,500 6. 99 7. 97 8. 9.1 9. 2,260 10. 55,168
1. 275,403 2. 695,394 3. 9 4. 100 5. 121 6. 12 7. 17,820 8. 28,512 27 9. 27 20 or 1 20 10. 33 35
1. 406.27 2. 30.6 3. 29 4. 1,774 5. 720 6. 300 3 7. 15 12 or 1 12 5 8. 10 or 16 8 9. 720 10. 150
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 2,525 2. 1,286 3. 2.3 4. 4,900 5. 67,200 6. 245 7. 237.1 8. 44.5 9. 23 10. 36
1. 390,695 2. 300,695 3. 25 4. 25 5. 25 6. 5 7. 17,216 8. 34,432 9. 95 or 1 45 10. 65 or 1 15
1. 814 2. 7.4 3. 2.6 4. 34.51 5. 334 6. 11,472 7. 70 8. 70 9. 39 or 13 10. 17 20
1. 2,626 2. 1,916 3. 3.81 4. 5,300 5. 49,000 6. 830 7. 6.4 8. 0.92 9. 672 10. 81
1. 978,986 2. 447,872 3. 5 4. 36 5. 49 6. 8 7. 79,902 8. 62,146 3 9. 11 8 or 1 8 6 10. 29 23 or 1 23
1. 41,926 2. 67,500 3. 0.92 4. 380.46 5. 90 6. 56,000 4 7. 18 7 or 2 7 5 8. 14 9. 362 10. 21,069
1. 7,633 2. 2,707 3. 5.74 4. 510 5. 6,300 6. 67 7. 81 8. 6.6 9. 4,110 10. 57,434
1. 674,395 2. 785,393 3. 12 4. 121 5. 100 6. 9 7. 31,437 8. 24,451 12 9. 33 21 or 1 21 1 10. 31 30 or 1 30
1. 229.82 2. 56.3 3. 45 4. 3,056 5. 350 6. 400 2 7. 14 12 or 1 12 8. 11 16 9. 450 10. 200
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
1,704
Yes, 40 x 90 = 3,600.
90
Yes, both equal No, the 80. difference is 34,607.
102
Yes, both equal Yes, 3,600 1,440. divided by 4 = 900.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 127
720,000
127
15/09/2022 09:59
ANSWERS Week 13: Week 13: Grasshopper Shinobi Monday Monday
Week 13: Week 14: Week 14: Grand Master Grasshopper Shinobi Monday Monday Monday
1. 27,636 2. 13,518 3. 10.87 4. 5.6 5. 270 6. 5 7. 0.8 8. 0.61 9. 0.08 10. 13.95
1. 490,807 2. 470,807 3. 60 4. 600 5. 6,000 6. 3 7. 30 8. 30 9. 78 10. 98 or 1 98
1. 600.4 2. 0.05 3. 0.36 4. 300,000 5. 35,000 6. 4,000 3 7. 15 12 or 1 12 20 4 8. 16 or 1 16 9. 350 10. 2,400
1. 9 2. 30 3. 7 4. 3.1 5. 4,500 6. 0.54 7. 0.76 8. 184 9. 1,141 10. 759
1. 211,098 2. 501,098 3. 56 4. 560 5. 5,600 6. 9 7. 90 8. 900 2 9. 10 15 or 3 16 1 10. 15 or 1 15
1. 26 2. 26 or 13 7 3. 12 7 4. 9 5. 49 6. 16 7. 15 17 8. 59 9. 140 10. 3,000
1. 11 2. 90 3. 8 4. 17 5. 560 6. 0.18 7. 42 8. 21 9. 357 10. 2,040
1. 433,910 2. 422,910 3. 0.5 4. 0.05 5. 0.005 6. 3 7. 30 8. 30,000 4 9. 12 or 13 2 10. 12 or 16
6 1. 10 or 35 18 3 2. 15 or 115 11 3. 22 or 30 15 4. 18 5. 14 6. 30 6 7. 19 7 8. 9 9. 40 10. 3,500
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 259,457 2. 249,457 3. 80 4. 800 5. 8,000 6. 4 7. 40 8. 40 7 9. 10 1 10. 11 10 or 1 10
1. 500.6 2. 0.04 3. 0.27 4. 120,000 5. 49,000 6. 7,200 6 7. 18 12 or 1 12 2 8. 18 or 1 16 16 9. 630 10. 2,100
1. 7 2. 90 3. 5 4. 3.2 5. 7,600 6. 0.25 7. 0.92 8. 280 9. 1,644 10. 1,004
1. 480,717 2. 372,717 3. 63 4. 630 5. 6,300 6. 8 7. 80 8. 800 8 9. 10 or 45 2 10. 12 10 or 1 10
2 1. 10 or 15 2. 59 9 3. 18 20 or 10 3 4. 14 5. 24 6. 36 7. 16 17 2 8. 11 9 or 19 9. 720 10. 1,500
Tuesday
1. 4,620 2. 8,730 3. 8.55 4. 5.7 5. 340 6. 7 7. 0.1 8. 0.63 9. 0.04 10. 18.5
1. 6 2. 70 3. 7 4. 54 5. 170 6. 0.24 7. 45 8. 132 9. 402 10. 1,701
1. 186,599 2. 107,599 3. 0.7 4. 0.07 5. 0.007 6. 4 7. 40 8. 400 9. 58 10. 18
1. 11 12 1 2. 17 16 or 1 16 7 3. 12 4. 48 or 12 5. 15 6. 35 4 7. 19 8. 39 or 13 9. 24 10. 2,100
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 144,358 2. 157,358 3. 90 4. 900 5. 9,000 6. 2 7. 20 8. 20 9. 56 10. 96 or 1 36
1. 300.5 2. 0.01 3. 0.69 4. 560,000 5. 81,000 6. 2,700 9 7. 22 13 or 1 13 6 8. 15 or 1 9 9 9. 270 10. 4,500
1. 8 2. 80 3. 4 4. 6.9 5. 1,200 6. 0.34 7. 0.84 8. 546 9. 1,160 10. 1,641
1. 528,880 2. 689,880 3. 71 4. 710 5. 7,100 6. 6 7. 60 8. 600 9. 79 4 10. 13 9 or 1 9
3 1. 10 2. 10 9 2 3. 10 15 or 5 3 4. 6 or 12 5. 48 6. 108 7. 10 11 8. 79 9. 550 10. 6,000
Wednesday
1. 13,220 2. 4,730 3. 5.73 4. 8.9 5. 740 6. 8 7. 0.6 8. 0.79 9. 0.02 10. 22.4
1. 3 2. 40 3. 7 4. 94 5. 450 6. 0.37 7. 54 8. 108 9. 434 10. 3,120
1. 312,160 2. 201,160 3. 0.9 4. 0.09 5. 0.009 6. 7 7. 70 8. 70,000 7 9. 10 1 10. 10
1. 13 14 2. 85 or 1 35 9 3. 14 2 4. 15 5. 36 6. 15 9 7. 14 8. 59 9. 40 10. 3,500
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 899,629 2. 591,629 3. 30 4. 300 5. 3,000 6. 5 7. 50 8. 50 9 9. 12 1 10. 13 12 or 1 12
1. 900.4 2. 0.06 3. 0.52 4. 810,000 5. 27,000 6. 5,400 6 7. 23 17 or 1 17 2 8. 11 or 1 9 9 9. 450 10. 3,000
1. 12 2. 90 3. 6 4. 4.3 5. 9,300 6. 0.71 7. 0.96 8. 528 9. 1,444 10. 2,667
1. 538,707 2. 420,707 3. 8.9 4. 89 5. 890 6. 4 7. 40 8. 400 9 9. 12 or 34 3 10. 15 12 or 1 12
3 1. 15 2. 10 12 9 3. 10 7 4. 12 5. 120 6. 54 7. 11 13 8. 79 9. 270 10. 4,000
Thursday
1. 28,370 2. 16,540 3. 3.28 4. 4.3 5. 320 6. 3 7. 0.9 8. 0.56 9. 0.08 10. 30.3
1. 3 2. 50 3. 9 4. 81 5. 630 6. 0.43 7. 72 8. 96 9. 268 10. 2,440
1. 400,011 2. 612,011 3. 0.8 4. 0.08 5. 0.008 6. 3 7. 30 8. 3,000 4 9. 12 or 13 3 10. 12 or 14
1. 67 3 2. 10 7 or 1 7 3 3. 4 4. 46 or 23 5. 27 6. 20 7. 38 8. 29 9. 120 10. 2,100
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 746,981 2. 549,981 3. 70 4. 700 5. 7,000 6. 6 7. 60 8. 60 9. 78 10. 98 or 1 18
1. 400.3 2. 0.05 3. 0.91 4. 360,000 5. 64,000 6. 900 10 7. 27 17 or 1 17 4 8. 13 9 or 1 9 9. 490 10. 1,000
1. 11 2. 90 3. 5 4. 1.7 5. 5,600 6. 0.85 7. 0.74 8. 234 9. 3,384 10. 2,277
1. 475,612 2. 583,612 3. 9.3 4. 93 5. 930 6. 7 7. 70 8. 700 8 9. 12 or 23 2 10. 14 12 or 1 12
2 1. 10 or 15 9 2. 15 or 35 4 3. 24 30 or 5 4. 38 5. 42 6. 96 7. 12 19 1 8. 10 9 or 1 9 9. 450 10. 4,500
Friday
1. 25,727 2. 4,629 3. 0.07 4. 2.9 5. 830 6. 7 7. 0.6 8. 0.48 9. 0.01 10. 35.2
1. 6 2. 90 3. 8 4. 45 5. 780 6. 0.39 7. 54 8. 84 9. 270 10. 1,287
1. 220,235 2. 3,235 3. 0.3 4. 0.03 5. 0.003 6. 9 7. 90 8. 90,000 1 9. 15 7 10. 15
1. 79 2. 97 or 1 27 3. 13 20 4. 17 5. 45 6. 24 7. 18 8. 79 9. 240 10. 2,700
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
630
No, 452 x 3 = 1,356.
65,794
3,221
9,000
30,000
4.52 minutes
5
Yes, 135 x 2 = 270 and 136 x 2 = 272
128
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 128
Week 14: Week 15: Week 15: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 15: Grand Master Monday
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
ANSWERS Week 16: Week 16: Grasshopper Shinobi Monday Monday
Week 16: Week 17: Week 17: Grand Master Grasshopper Shinobi Monday Monday Monday
1. 74,359 2. 587,359 3. 5.3 4. 0.53 5. 0.053 6. 7 7. 70 8. 7,000 9. 13 20 9 10. 20
1. 621,446 2. 8,909 3. 3.84 4. 410 5. 0.149 4 6. 11 7 or 1 7 5 7. 10 or 12 6 8. 12 9. 350 10. 1,800
1. 456,492 2. 748,675 3. 40 4. 0.4 5. 0.04 6. 3 7. 9 8. 90 2 9. 12 or 16 14 2 10. 12 or 1 12
1. 104,384 2. 347,087 3. 11.34 4. 1.2 5. 5,700 8 6. 23 15 or 1 15 8 7. 12 or 23 8. 30 9. 420 10. 2,700
4 1. 10 6 or 1 6 5 2. 12 3. 984 4. 3.52 5. 14.6 6. 56 7. 45 8. 310 9. 864 10. 645,856
Week 18: Grand Master Monday
1. 9 2. 28 3. 63 4. 40 5. 0.45 6. 8 7. 42 8. 60 9. 261 10. 1,030
1. 87 or 1 17 5 2. 16 3. 5,166 4. 16 5. 62 6. 97 7. 0.08 8. 4 9. 364 10. 924
Week 17: Week 18: Week 18: Grand Master Grasshopper Shinobi Monday Monday Monday 1. 384,493 2. 403,887 3. 3,450 4. 3.45 5. 34.5 6. 4 7. 28 8. 2,800 9. 13 18 3 10. 21 18 or 1 18
1. 317,261 2. 405,712 3. 5,620 4. 105.4 5. 96 6. 34 7. 16 8. 24 9. 450 10. 4,500
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 442,535 2. 133,000 3. 4.31 4. 190 5. 0.235 3 6. 11 8 or 1 8 9 7. 18 20 or 10 8. 24 9. 540 10. 2,500
1. 586,593 2. 375,423 3. 6,000 4. 0.06 5. 600 6. 7 7. 21 8. 210 5 9. 15 or 13 5 10. 20 15 or 1 15
1. 203,775 2. 256,713 3. 12.67 4. 3.6 5. 1,300 12 6. 29 17 or 1 17 7 7. 16 8. 54 9. 350 10. 1,600
1. 86 or 1 26 5 2. 12 3. 695 4. 1.28 5. 7.8 6. 62 7. 58 8. 355 9. 1,456 10. 481,176
Tuesday
1. 629,329 2. 418,329 3. 6.7 4. 0.67 5. 0.067 6. 5 7. 50 8. 5,000 2 9. 12 or 16 8 10. 12 or 23
3 1. 10 7 or 1 7 2 2. 16 or 18 3. 8,737 4. 21 5. 93 6. 35 7. 0.12 8. 8 9. 196 10. 1,068
Tuesday
1. 6 2. 31 3. 56 4. 140 5. 0.71 6. 6 7. 84 8. 72 9. 260 10. 1,296
1. 473,495 2. 342,947 3. 57,600 4. 5.76 5. 0.576 6. 3 7. 15 8. 1,500 2 9. 12 or 16 8 10. 20 12 or 1 12
1. 219,276 2. 398,833 3. 7,956 4. 114.3 5. 72 6. 24 7. 28 or 14 8. 55 9. 320 10. 5,600
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 535,022 2. 233,867 3. 5.07 4. 480 5. 0.308 5 6. 13 8 or 1 8 11 7. 12 8. 15 9. 630 10. 5,600
1. 594,394 2. 583,483 3. 900 4. 0.009 5. 0.9 6. 7 7. 35 8. 3,500 9. 19 1 10. 10 9 or 1 9
1. 236,771 2. 376,089 3. 13.43 4. 4.8 5. 2,700 8 6. 19 11 or 1 11 4 1 7. 8 or 2 8. 36 9. 180 10. 7,200
1. 97 or 1 27 2 2. 15 3. 531 4. 6.5 5. 7.3 6. 73 7. 62 8. 375 9. 2,205 10. 397,112
Wednesday
1. 554,971 2. 588,971 3. 9.8 4. 0.98 5. 0.098 6. 9 7. 90 8. 9,000 9. 14 25 4 10. 25
5 1. 14 9 or 1 9 5 2. 19 3. 7,954 4. 24 5. 59 6. 41 7. 0.31 8. 8 9. 344 10. 2,040
Wednesday
1. 7 2. 33 3. 82 4. 80 5. 0.17 6. 9 7. 56 8. 27 9. 365 10. 2,184
1. 198,594 2. 523,077 3. 8,090 4. 8.09 5. 0.809 6. 6 7. 18 8. 1,800 3 9. 10 5 10. 15 10 or 1 10
1. 302,311 2. 400,310 3. 6,522 4. 109.8 5. 38 6. 45 5 7. 10 14 or 7 8. 30 9. 210 10. 3,600
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 663,390 2. 98,313 3. 7.55 4. 710 5. 0.414 1 6. 16 15 or 1 15 14 7 7. 18 or 9 8. 18 9. 270 10. 8,400
1. 596,394 2. 342,808 3. 20 4. 0.2 5. 0.002 6. 8 7. 40 8. 4,000 8 9. 20 or 45 2 10. 22 20 or 1 20
1. 421,274 2. 258,423 3. 15.61 4. 6.1 5. 4,100 6 6. 17 11 or 1 11 4 2 7. 10 or 5 8. 56 9. 420 10. 4,000
4 1. 11 7 or 1 7 5 2. 15 or 13 3. 383 4. 7.19 5. 11.3 6. 77 7. 71 8. 456 9. 2,488 10. 278,894
Thursday
1. 390,101 2. 502,101 3. 5.2 4. 0.52 5. 0.052 6. 11 7. 110 8. 11,000 5 9. 10 18 or 9 7 10. 18
7 1. 16 9 or 1 9 8 2. 19 3. 7,954 4. 15 5. 121 6. 90 7. 0.27 8. 8 9. 266 10. 2,349
Thursday
1. 4 2. 23 3. 91 4. 340 5. 0.64 6. 7 7. 35 8. 54 9. 444 10. 2,024
1. 484,394 2. 354,354 3. 39,000 4. 3.9 5. 0.39 6. 9 7. 27 8. 2,700 7 9. 15 4 10. 19 15 or 1 15
1. 119,238 2. 546,733 3. 10,801 4. 130.3 5. 52 6. 67 7. 19 8. 42 9. 540 10. 5,600
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 435,640 2. 168,070 3. 8.61 4. 850 5. 0.573 5 6. 20 15 or 1 15 7. 11 12 8. 27 9. 800 10. 7,000
1. 475,424 2. 552,916 3. 5,500 4. 0.55 5. 5.5 6. 2 7. 14 8. 1,400 7 9. 18 10. 17 18
1. 409,612 2. 278,401 3. 13.41 4. 4.7 5. 9,600 6 6. 15 9 or 1 9 5 7. 10 or 12 8. 35 9. 810 10. 5,600
7 1. 16 9 or 1 9 4 2. 19 3. 194 4. 5.69 5. 10.1 6. 83 7. 78 8. 567 9. 2,824 10. 111,221
Friday
1. 449,479 2. 555,480 3. 2.5 4. 0.25 5. 0.025 6. 8 7. 80 8. 8,000 5 9. 20 or 14 4 10. 20 or 15
7 1. 19 12 or 1 12 6 2. 11 3. 6,829 4. 17 5. 143 6. 11 7. 0.46 8. 12 9. 344 10. 1,617
Friday
1. 12 2. 25 3. 123 4. 60 5. 0.83 6. 4 7. 132 8. 99 9. 504 10. 1,455
1. 475,493 2. 632,978 3. 607,000 4. 60.7 5. 6.07 6. 8 7. 56 8. 56,000 3 9. 16 7 10. 23 16 or 1 16
1. 217,331 2. 478,001 3. 11,249 4. 140.1 5. 22 6. 57 7. 36 or 12 8. 60 9. 900 10. 7,000
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
910
52,620
14,666
No, the total is 9,000.
No, 4,834 more No, the total is than 9,985 is 122,978. 14,819.
659
No, both are equal to 29,005.
63,000
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 129
129
15/09/2022 09:59
ANSWERS Week 19: Week 19: Grasshopper Shinobi Monday Monday
Week 19: Week 20: Week 20: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 20: Week 21: Week 21: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 21: Grand Master Monday
6 1. 18 12 or 1 12 3 1 2. 21 or 7 3. 43 4. 6.55 5. 1.8 6. 45 7. 954 8. 152,762 9. 10.5 10. 4.25
1. 604,395 2. 571,395 3. 564,475 4. 8,294 5. 4,653 6. 3 7. 6 8. 12 3 9. 27 8 or 3 8 23 10. 8 or 2 78
1. 448,644 2. 290,038 3. 9,858 4. 259 5. 1.76 6. 82.6 7. 313,121 8. 451,342 9. 200,426 10. 220,034
1. 17 2. 40.3 3. 5.61 4. 0.005 5. 560 6. 0.26 7. 4,600 8. 0.125 5 9. 20 15 or 1 15 3 10. 11
1. 391,395 2. 385,295 3. 424,395 4. 3,795 5. 9,504 6. 12 7. 60 8. 96 1 9. 19 9 or 2 9 22 4 10. 9 or 2 9
1. 665,371 2. 203,281 3. 11,277 4. 299 5. 299 6. 456 7. 73,382 8. 102,183 9. 231,102 10. 512,283
1. 93 2. 10.5 3. 1.39 4. 0.014 5. 54 6. 0.71 7. 6,100 8. 0.732 14 9. 30 16 or 1 16 4 1 10. 20 or 5
1. 262,893 2. 173,293 3. 255,293 4. 1,035 5. 3,105 6. 32,085 7. 28 8. 280,000 9. 78 10. 38
1. 70 2. 123 3. 403 4. 9,288 5. 1,620 6. 4,114 7. 4,000 8. 3,000 9. 6 10. 9
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 677,392 2. 679,392 3. 674,482 4. 5,863 5. 5,423 6. 7 7. 28 8. 35 1 9. 31 6 or 5 6 3 10. 26 or 4 6 6
1. 317,742 2. 232,985 3. 5,187 4. 312 5. 2.78 6. 76.3 7. 91,353 8. 300,102 9. 381,283 10. 110,264
1. 56 2. 31.5 3. 2.31 4. 0.007 5. 670 6. 0.14 7. 5,100 8. 0.203 5 9. 20 15 or 1 15 1 10. 11
1. 513,384 2. 423,464 3. 431,384 4. 4,312 5. 7,183 6. 9 7. 45 8. 99 3 9. 51 12 or 4 12 9 10. 57 or 4 12 12
1. 512,271 2. 332,203 3. 9,612 4. 311 5. 345 6. 736 7. 98,171 8. 232,287 9. 145,351 10. 104,472
1. 84 2. 11.1 3. 4.51 4. 0.023 5. 27 6. 0.83 7. 1,200 8. 0.106 7 9. 23 16 or 1 16 6 3 10. 20 or 10
1. 227,247 2. 165,247 3. 235,157 4. 3,265 5. 5,877 6. 38,527 7. 160 8. 1,600 7 9. 31 8 or 3 8 5 10. 29 or 3 8 8
1. 70 2. 243 3. 445 4. 9,058 5. 1,628 6. 3,168 7. 3,000 8. 7,000 9. 4 10. 9
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 324,593 2. 284,643 3. 291,593 4. 4,334 5. 8,393 6. 4 7. 16 8. 28 2 9. 20 9 or 2 9 1 10. 19 or 2 9 9
1. 425,446 2. 312,570 3. 7,155 4. 366 5. 4.07 6. 60.4 7. 228,101 8. 302,283 9. 614,332 10. 285,371
1. 78 2. 21.8 3. 4.56 4. 0.009 5. 120 6. 0.19 7. 7,800 8. 0.341 8 9. 18 10 or 1 10 3 10. 15 or 15
1. 196,292 2. 275,492 3. 202,492 4. 2,585 5. 9,515 6. 12 7. 60 8. 108 23 9. 48 25 or 1 25 4 10. 54 or 2 25 25
1. 481,266 2. 203,371 3. 10,566 4. 351 5. 700 6. 1,302 7. 101,183 8. 663,788 9. 255,321 10. 176,545
1. 77 2. 30.6 3. 7.03 4. 0.045 5. 61 6. 0.73 7. 4,600 8. 0.217 9 9. 25 16 or 1 16 1 10. 10 or 20 2
1. 379,203 2. 384,163 3. 383,403 4. 1,729 5. 741 6. 9,139 7. 140 8. 14,000 9. 56 10. 96 or 1 36
1. 90 2. 176 3. 398 4. 7,392 5. 1,472 6. 3,597 7. 4,000 8. 5,000 9. 8 10. 7
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 273,493 2. 202,493 3. 194,293 4. 6,446 5. 7,073 6. 9 7. 27 8. 63 1 9. 25 8 or 3 8 5 10. 29 or 3 8 8
1. 508,287 2. 418,003 3. 13,216 4. 351 5. 6.81 6. 43.8 7. 188,281 8. 413,361 9. 704,203 10. 322,331
1. 94 2. 30.5 3. 5.01 4. 0.001 5. 320 6. 0.26 7. 4,600 8. 0.561 5 9. 15 10 or 1 10 4 10. 15
1. 453,391 2. 393,461 3. 401,391 4. 3,762 5. 7,073 6. 9 7. 45 8. 81 9 9. 25 16 or 1 16 15 10. 31 or 1 16 16
1. 373,271 2. 172,869 3. 14,778 4. 395 5. 918 6. 1,485 7. 126,262 8. 473,281 9. 641,253 10. 153,577
1. 63 2. 41.9 3. 8.13 4. 0.068 5. 82 6. 0.45 7. 1,900 8. 0.823 14 9. 31 17 or 1 17 6 10. 26
1. 962,884 2. 955,384 3. 873,384 4. 2,142 5. 2,856 6. 24,276 7. 150 8. 150,000 1 9. 17 8 or 2 8 7 10. 15 or 1 8 8
1. 70 2. 92 3. 472 4. 12,816 5. 1,404 6. 4,032 7. 7,000 8. 9,000 9. 3 10. 7
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 695,365 2. 703,565 3. 734,565 4. 10,318 5. 1,353 6. 7 7. 28 8. 49 11 9. 26 15 or 1 15 2 10. 32 15 or 2 15
1. 521,329 2. 113,833 3. 14,976 4. 373 5. 7.05 6. 37.4 7. 195,361 8. 200,281 9. 72,361 10. 427,201
1. 81 2. 45.2 3. 6.22 4. 0.005 5. 540 6. 0.39 7. 5,100 8. 0.805 5 9. 19 14 or 1 14 7 10. 16
1. 354,291 2. 274,371 3. 281,291 4. 2,574 5. 4,334 6. 9 7. 63 8. 81 13 9. 41 14 or 2 14 3 10. 45 14 or 3 14
1. 290,003 2. 102,038 3. 15,939 4. 404 5. 1,044 6. 1,036 7. 111,073 8. 503,281 9. 333,267 10. 90,104
1. 76 2. 60.8 3. 9.14 4. 0.091 5. 67 6. 0.86 7. 9,400 8. 0.184 13 9. 32 19 or 1 19 2 1 10. 26 or 13
1. 44,242 2. 117,241 3. 123,741 4. 4,203 5. 1,401 6. 18,213 7. 300 8. 30,000 7 9. 15 8 or 1 8 3 10. 19 8 or 2 8
1. 90 2. 137 3. 604 4. 15,840 5. 1,833 6. 5,166 7. 8,000 8. 3,000 9. 3 10. 8
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
3,880
800
Yes,18 of 640 is 80 and 3 x 80 is 240.
No, 5,500 – 900 Yes, 512 x 5 = = 4,600. 2,560.
2,105
No, 90,005 more than 98,010 is equal to 179,015.
8 1. 20 12 or 1 12 8 2. 21 3. 63 4. 6.55 5. 5.1 6. 65 7. 896 8. 162,646 9. 21.3 10. 4.71
Wednesday 11 1. 26 15 or 1 15 2. 89 3. 71 4. 4.63 5. 1.7 6. 68 7. 623 8. 86,595 9. 33.4 10. 5.63
Thursday
6 1. 21 15 or 1 15 2. 39 or 13 3. 84 4. 6.48 5. 2.7 6. 76 7. 455 8. 93,572 9. 51.3 10. 6.12
Friday
2 1. 17 15 or 1 15 1 2. 10 3. 93 4. 5.82 5. 2.1 6. 83 7. 539 8. 90,113 9. 62.7 10. 5.61
130
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 130
Yes. 90,384 Iko – Iko has – 56,000 = 5,370, Sam has 34,384. 34,384 5,360. – 588 = 33,796.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
ANSWERS Week 22: Week 22: Grasshopper Shinobi Monday Monday
Week 22: Week 23: Week 23: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 23: Week 24: Week 24: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 24: Grand Master Monday
1. 7.6 2. 0.413 3. 0.236 4. 0.52 5. 330 6. 7.6 7. 59 8. 1.29 9. 24 12 or 2 9 10. 25
1. 318,584 2. 286,584 3. 325,684 4. 3,500 5. 4,375 6. 47,250 7. 490 8. 4,900 8 9. 23 15 or 1 15 20 5 10. 15 or 1 15
1. 360 2. 987 3. 3,906 4. 15,606 5. 1,215 6. 17,466 7. 9,000 8. 3,000 9. 85 or 1 35 8 10. 10
1. 90,000 2. 310,000 3. 24 4. 0.24 5. 2.4 6. 45 7. 7.03 8. 56 9. 224 10. 76
1. 855,294 2. 847,794 3. 778,294 4. 19,272 5. 9,768 6. 408 7. 400 8. 2,000 2 9. 20 9 or 2 9 10 10. 9 or 1 19
1. 7 2. 176 3. 532 4. 12,528 5. 1,015 6. 9,159 8 7. 14 or 47 21 1 8. 20 or 120 9. 85 or 1 35 6 10. 12 14 or 7
1. 46,560 2. 67,670 3. 31 4. 0.31 5. 47 6. 1.504 3 7. 10 3 8. 4 9. 760 10. 154
1. 341,395 2. 287,395 3. 290,595 4. 46,272 5. 80,976 6. 584 7. 600 8. 1,200 13 9. 43 15 or 2 15 28 10. 15 or 113 15
1. 9.45 2. 100 3. 1,268 4. 3,024 5. 9,150 6. 8,815 7 7. 15 4 8. 8 or 12 5 9. 15 10 or 1 10 9 10. 9 or 1
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 3.2 2. 0.562 3. 0.133 4. 0.54 5. 520 6. 9.4 7. 72 8. 3.04 6 9. 18 12 or 1 12 5 10. 25 or 15
1. 413,134 2. 419,334 3. 370,134 4. 4,325 5. 7,785 6. 82,175 7. 360 8. 36,000 7 9. 16 9 or 1 9 2 10. 20 or 2 9 9
1. 480 2. 959 3. 4,122 4. 18,657 5. 1,632 6. 12,388 7. 4,000 8. 11,000 3 9. 12 9 or 1 9 4 10. 12 or 15 5
1. 110,000 2. 240,000 3. 55 4. 0.55 5. 5.5 6. 74 7. 6.27 7 8. 12 9. 365 10. 84
1. 376,794 2. 385,494 3. 294,794 4. 17,595 5. 24,480 6. 188 7. 700 8. 3,500 7 9. 57 10 or 5 10 5 10 45 or 4 10 10
1. 8 2. 183 3. 546 4. 12,216 5. 1,634 6. 9,159 7. 88 or 1 8. 76 or 1 16 4 9. 10 6 or 1 6 4 10. 16 or 20 5
1. 37,360 2. 60,270 3. 59 4. 0.59 5. 67 6. 2.364 7. 49 8. 46 or 23 9. 1,210 10. 179
1. 856,094 2. 915,294 3. 924,094 4. 10,148 5. 16,340 6. 325 7. 7,000 8. 35,000 7 9. 23 8 or 2 8 5 10. 21 or 2 8 8
1. 11.39 2. 10 3. 1,095 4. 1,392 5. 7,496 6. 5,168 5 7. 10 3 8. 11 8 or 1 8 6 9. 18 12 or 1 12 5 10. 15 or 1 10 10
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 5.6 2. 0.284 3. 0.152 4. 0.51 5. 590 6. 2.5 7. 69 8. 2.83 3 9. 15 12 or 1 12 8 10. 25
1. 924,623 2. 918,023 3. 855,023 4. 1,389 5. 3,241 6. 33,799 7. 240 8. 24,000 1 9. 21 10 or 2 10 9 10. 19 or 1 10 10
1. 360 2. 873 3. 4,239 4. 14,469 5. 1,924 6. 11,835 7. 7,000 8. 7,000 2 9. 14 12 or 1 12 4 10. 12 or 15 5
1. 50,000 2. 250,000 3. 33 4. 0.33 5. 3.3 6. 83 7. 3.26 3 8. 10 9. 924 10. 98
1. 774,024 2. 693,324 3. 686,024 4. 47,768 5. 55,445 6. 365 7. 1,200 8. 3,600 13 9. 41 14 or 2 14 11 10. 25 or 1 14 14
1. 9 2. 194 3. 556 4. 18,004 5. 1,886 6. 10,088 2 7. 12 10 or 1 10 8. 58 1 9. 25 8 or 3 8 6 10. 12 or 12
1. 57,370 2. 49,370 3. 24 4. 0.24 5. 78 6. 2.006 4 7. 12 or 13 8. 49 9. 1,820 10. 245
1. 905,503 2. 874,803 3. 897,803 4. 10,638 5. 28,368 6. 654 7. 120,000 8. 480,000 3 9. 39 12 or 3 12 3 10. 15 or 1 12 12
1. 14.27 2. 100 3. 2,464 4. 1,872 5. 3,702 6. 11,948 2 7. 10 7 8. 16 9 or 1 9 18 1 9. 17 or 117 3 10. 15 or 3 4 4
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 8.5 2. 0.363 3. 0.179 4. 0.63 5. 290 6. 5.2 7. 81 8. 2.71 3 9. 19 16 or 1 16 7 10. 14 or 30 15
1. 772,149 2. 795,149 3. 801,549 4. 6,112 5. 3,820 6. 44,312 7. 160 8. 1,600 7 9. 25 9 or 2 9 1 10. 28 or 3 9 9
1. 270 2. 918 3. 2,751 4. 12,412 5. 1,980 6. 14,064 7. 8,000 8. 6,000 6 9. 18 12 or 1 12 10. 69 or 23
1. 250,000 2. 370,000 3. 88 4. 0.88 5. 8.8 6. 79 7. 1.64 8. 36 or 12 9. 2,692 10. 103
1. 138,384 2. 217,384 3. 207,784 4. 24,990 5. 17,052 6. 286 7. 600 8. 1,800 3 9. 21 6 or 3 6 3 10. 33 or 5 6 6
1. 9 2. 203 3. 612 4. 15,375 5. 1,813 6. 8,432 1 7. 10 9 or 1 9 3 8. 10 6 9. 20 7 or 2 7 9 10. 13
1. 28,280 2. 64,170 3. 1 4. 0.01 5. 0.2 6. 4.739 4 7. 15 5 8. 12 9. 2,255 10. 373
1. 475,037 2. 387,037 3. 394,637 4. 55,722 5. 35,391 6. 326 7. 70,000 8. 490,000 3 9. 33 10 or 3 10 5 10. 15 or 1 10 10
1. 6.07 2. 10 3. 2,556 4. 1,557 5. 3,590 6. 13,195 1 7. 10 7 8. 17 10 or 1 10 27 7 9. 10 or 210 3 10. 18 or 5 5 5
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 9.3 2. 0.415 3. 0.235 4. 0.43 5. 670 6. 8.3 7. 45 8. 8.31 4 9. 20 16 or 1 16 10. 13 30
1. 830,192 2. 904,192 3. 909,692 4. 5,696 5. 2,136 6. 27,056 7. 180 8. 1,800 9. 17 9 10. 19 9
1. 840 2. 954 3. 3,296 4. 21,060 5. 1,512 6. 10,850 7. 5,000 8. 7,000 4 9. 18 14 or 1 14 9 10. 11
1. 220,000 2. 400,000 3. 63 4. 0.63 5. 6.3 6. 49 7. 5.04 8. 38 9. 2,842 10. 121
1. 353,291 2. 277,291 3. 282,691 4. 21,356 5. 46,646 6. 124 7. 200 8. 800 3 9. 43 20 or 2 20 10. 11 20
1. 12 2. 254 3. 641 4. 18,291 5. 2,976 6. 10,382 7 7. 22 15 or 1 15 8. 12 12 or 1 1 9. 10 9 or 1 9 4 10. 12 15 or 5
1. 58,270 2. 59,370 3. 99 4. 0.99 5. 1.3 6. 6.046 3 7. 20 5 8. 20 or 14 9. 2,445 10. 398
1. 317,827 2. 259,827 3. 310,427 4. 6,364 5. 12,556 6. 142 7. 300 8. 2,100 4 9. 28 12 or 2 12 8 10. 12 or 23
1. 19.45 2. 100 3. 2,177 4. 3,726 5. 1,630 6. 7,728 5 7. 12 4 8. 16 6 or 2 6 6 9. 18 or 1 12 12 10. 21 7 or 3
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Tom – Tom has 3,390, Cho has 3,290.
Yes, 7,200 divided by 8 = 900.
9
Iko has 6,000.
196,471
5,040
No, they are equal, they are both 500.
Yes, both are equal to 40,000.
6,000
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
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ANSWERS Week 25: Week 25: Grasshopper Shinobi Monday Monday
Week 25: Week 26: Week 26: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 26: Week 27: Week 27: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 27: Grand Master Monday
1. 62,232 2. 38,307 3. 130 4. 0.646 5. 335,312 6. 125,390 6 7. 10 or 35 3 8. 10 9. 570 10. 83
1. 535,294 2. 484,594 3. 477,294 4. 15,399 5. 24,795 6. 592 7. 9,000 8. 45,000 3 9. 33 6 or 5 6 19 10. 6 or 3 16
1. 6.95 2. 0.26 3. 3 4. 5 5. 713 6. 406 2 7. 12 or 16 15 8. 6 or 2 36 4 9. 10 6 or 1 6 25 10. 6 or 4 16
1. 64,506 2. 51,040 3. 198,383 4. 114,255 5. 120 6. 280 4 7. 18 or 29 11 8. 30 9. 546 10. 89
1. 7.3 2. 47.3 3. 47.38 4. 235 5. 470 6. 7 7. 2 8. 58 9. 78 10. 3
1. 40 2. 30 3. 70 4. 80 5. 34 6. 56 7. 73 8. 7.6 9. 4.5 10. 9.2
1. 36 2. 360 3. 42 4. 420 5. 30 6. 300 7. 58 7 8. 24 9. 288 10. 56
1. 10.3 2. 10.41 3. 40.41 4. 325 5. 329 6. 50 7. 10 8. 17 20 9. 11 20 10. 13
1. 130 2. 4,900 3. 71 4. 620 5. 10.7 6. 278 7. 62.8 8. 3 9. 6.1 10. 0.2
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 46,344 2. 49,427 3. 650 4. 0.153 5. 217,373 6. 191,374 7. 49 6 8. 15 or 25 9. 558 10. 73
1. 913,394 2. 920,484 3. 919,694 4. 21,204 5. 27,900 6. 854 7. 900 8. 2,700 2 9. 62 10 or 6 10 2 10. 52 or 5 10 10
1. 26.79 2. 1.45 3. 6 4. 5 5. 428 6. 385 7. 18 3 8. 33 10 or 3 10 4 9. 20 8 or 2 8 4 10. 10 6 or 1 6
1. 16,382 2. 24,703 3. 204,143 4. 190,292 5. 90 6. 420 3 7. 18 8. 36 or 12 9. 623 10. 105
1. 12.3 2. 12.35 3. 42.35 4. 458 5. 916 6. 8 7. 2 8. 37 9. 27 10. 5
1. 400 2. 500 3. 900 4. 20 5. 60 6. 51 7. 96 8. 2.3 9. 6.2 10. 17.4
1. 72 2. 720 3. 35 4. 350 5. 9 6. 90 5 7. 12 3 8. 10 9. 352 10. 55
1. 11.3 2. 11.43 3. 61.43 4. 378 5. 382 6. 4 7. 5 8. 17 24 9. 19 24 10. 7
1. 4,170 2. 36,300 3. 184 4. 2,340 5. 549 6. 315 7. 21.9 8. 0.3 9. 9.3 10. 0.5
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 24,314 2. 64,371 3. 830 4. 0.364 5. 130,380 6. 305,305 3 7. 14 3 8. 16 9. 630 10. 99
1. 364,213 2. 286,213 3. 293,513 4. 8,232 5. 24,108 6. 256 7. 7,000 8. 28,000 9 9. 33 12 or 2 12 7 10. 12
1. 17.91 2. 0.03 3. 8 4. 9 5. 639 6. 438 2 7. 16 or 18 8. 49 6 9. 15 9 or 1 9 4 10. 25 or 3 7 7
1. 42,284 2. 21,322 3. 330,147 4. 159,937 5. 210 6. 700 7 7. 18 8. 46 or 23 9. 651 10. 125
1. 12.3 2. 12.36 3. 72.36 4. 286 5. 572 6. 6 7. 60 7 8. 12 5 9. 12 10. 11
1. 700 2. 300 3. 80 4. 10 5. 67 6. 29 7. 7.9 8. 1.3 9. 26.7 10. 67.1
1. 64 2. 640 3. 108 4. 1,080 5. 20 6. 200 4 7. 12 or 13 4 8. 15 9. 496 10. 72
1. 13.5 2. 13.65 3. 53.65 4. 543 5. 552 6. 4 7. 60 8. 13 19 9. 14 19 10. 17
1. 23,000 2. 457,000 3. 25,100 4. 12,150 5. 1,534 6. 5,310 7. 121 8. 143 9. 12.4 10. 6
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 43,188 2. 77,252 3. 710 4. 0.637 5. 102,374 6. 277,005 3 7. 18 or 16 3 8. 22 9. 1,458 10. 109
1. 858,293 2. 943,293 3. 937,693 4. 14,532 5. 8,304 6. 785 7. 20,000 8. 80,000 7 9. 21 14 or 1 14 10. 13 14
1. 31.21 2. 0.17 3. 6 4. 8 5. 526 6. 544 2 7. 14 or 17 8 8. 15 6 9. 24 9 or 2 9 4 10. 18 or 2 7 7
1. 19,290 2. 20,008 3. 700,404 4. 101,001 5. 430 6. 920 4 7. 18 5 8. 12 9. 987 10. 130
1. 8.7 2. 48.7 3. 48.76 4. 356 5. 712 6. 2 7. 8 3 8. 12 or 14 6 9. 12 or 12 10. 9
1. 750 2. 140 3. 82 4. 19 5. 67.5 6. 29.1 7. 8.3 8. 2.6 9. 10.9 10. 50.2
1. 36 2. 360 3. 49 4. 490 5. 16 6. 160 5 7. 12 3 8. 14 9. 592 10. 82
1. 11.1 2. 11.25 3. 71.25 4. 85 5. 97 6. 3 7. 9 8. 15 27 9. 13 27 10. 23
1. 47,100 2. 943,000 3. 61,400 4. 18,470 5. 1,325 6. 4,780 7. 254 8. 365 9. 45.9 10. 6.6
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 36,460 2. 78,095 3. 590 4. 0.183 5. 200,293 6. 99,304 9 7. 20 5 8. 12 9. 1,122 10. 154
1. 344,028 2. 277,028 3. 283,328 4. 15,088 5. 5,152 6. 421 7. 5,000 8. 25,000 10 9. 55 15 or 3 15 10 10. 25 15 or 1 15
1. 38.26 2. 1.06 3. 4 4. 9 5. 491 6. 578 5 7. 18 5 8. 10 12 or 6 9. 30 or 3 10 2 10. 12 5 or 2 5
1. 44,302 2. 33,290 3. 560,461 4. 202,103 5. 410 6. 1,020 3 7. 18 or 16 9 8. 20 9. 1,071 10. 163
1. 8.2 2. 8.28 3. 38.28 4. 254 5. 508 6. 20 7. 20 8. 11 16 9. 15 16 10. 5
1. 670 2. 260 3. 91 4. 45 5. 19.5 6. 36.7 7. 14.2 8. 0.7 9. 1.4 10. 0.2
1. 48 2. 480 3. 63 4. 630 5. 36 6. 360 3 7. 12 or 14 6 8. 15 9. 712 10. 103
1. 9.5 2. 69.5 3. 69.63 4. 126 5. 132 6. 6 7. 3 8. 11 27 9. 26 27 10. 25
1. 56,200 2. 713,000 3. 84,300 4. 23,850 5. 4,539 6. 7,310 7. 643 8. 197 9. 60.4 10. 7.5
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Yes, 280 is greater than 270.
No, 57,684 – No, the answer 11,004 49,576 = 8,108. is 107,910.
2,400
295,790
9,002
No, 20.5 – 14.4 = 6.1.
400
132
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15/09/2022 09:59
ANSWERS Week 28: Week 28: Grasshopper Shinobi Monday Monday
Week 28: Week 29: Week 29: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 29: Week 30: Week 30: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 30: Grand Master Monday
1. 182 2. 276 3. 34 4. 45 1 5. 11 5 or 2 5 6. 100 7. 79 8. 56 9. 486 10. 67
1. 3.4 2. 3.37 3. 13.37 4. 117.5 5. 128.5 6. 10 7. 9 8. 48 or 12 9. 68 or 34 10. 98 or 1 18
1. 17,300 2. 840,000 3. 41,300 4. 34,370 5. 6,741 6. 8,560 7. 561 8. 174 9. 0.95 10. 7.5
1. 651 2. 462 9 3. 14 8 4. 13 5. 94 or 2 14 6. 45 5 7. 12 13 8. 16 9. 6 10. 12
1. 2.8 2. 2.76 3. 12.76 4. 172.4 5. 175.8 6. 5 7. 10 8. 24 25 3 9. 15 25 or 5 28 3 10. 25 or 1 25
1. 64,500 2. 4,510 3. 36,400 4. 17,340 5. 4,567 6. 72.3 7. 511 8. 761 9. 5.92 10. 0.264
1. 504 8 2. 12 or 23 3. 83 or 2 23 4. 85 or 1 35 5. 14 8 6. 15 8 7. 12 or 23 8. 8,889 9. 9.95 10. 8.45
1. 2.35 2. 2.91 3. 4.39 4. 186.5 5. 74.6 6. 512 7. 1,625 7 8. 15 8 or 1 8 3 9. 10 or 1 7 7 12 10. 9 or 1 39
1. 67,100 2. 564.6 3. 8.91 4. 104.2 5. 180 6. 2,700 7. 215 8. 600 9. 150 10. 85
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 195 2. 224 3. 36 or 12 4. 47 3 5. 13 5 or 2 5 6. 40 7. 58 8. 79 9. 549 10. 82
1. 5.6 2. 35.6 3. 35.59 4. 483.5 5. 487.5 6. 40 7. 20 8. 68 or 34 9. 48 or 12 10. 68 or 34
1. 24,500 2. 914,000 3. 56,200 4. 17,490 5. 5,125 6. 9,130 7. 648 8. 209 9. 1.36 10. 6.2
1. 455 2. 294 6 3. 12 14 or 7 6 4. 13 3 5. 21 6 or 3 6 6. 20 8 7. 16 30 or 15 5 8. 10 or 12 6 9. 6 10. 6
1. 2.5 2. 12.5 3. 12.46 4. 125.6 5. 139.4 6. 20 7. 2 8. 25 27 9. 24 27 1 10. 28 27 or 1 27
1. 71,400 2. 2,740 3. 31,100 4. 15,270 5. 3,737 6. 95.6 7. 174 8. 291 9. 7.58 10. 0.775
1. 736 2. 89 3. 12 4 or 3 3 4. 13 5 or 2 5 5. 24 2 6. 10 15 or 3 5 7. 10 12 or 6 8. 5,179 9. 14.98 10. 11.34
1. 4.44 2. 4.65 3. 7.11 4. 221.5 5. 177.2 6. 248 7. 1,605 6 8. 20 7 or 2 7 8 9. 24 16 or 1 16 3 10. 18 or 1 15 15
1. 58,300 2. 712.7 3. 6.28 4. 121.4 5. 285 6. 3,150 7. 230 8. 700 9. 84 10. 124
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 238 2. 192 3. 38 4. 69 3 5. 21 6 or 3 6 6. 80 5 7. 10 or 12 9 8. 12 or 34 9. 603 10. 87
1. 3.1 2. 3.13 3. 13.13 4. 391.5 5. 396.5 6. 18 7. 12 4 8. 12 15 or 5 10 2 9. 15 or 3 1 10. 16 15 or 1 15
1. 36,500 2. 459,000 3. 21,700 4. 24,670 5. 6,846 6. 5,250 7. 871 8. 374 9. 2.36 10. 15.3
1. 280 2. 704 3. 36 or 12 4. 69 or 23 5 5. 17 6 or 2 6 6. 28 7 7. 10 8. 58 9. 12 10. 4
1. 2.7 2. 2.66 3. 62.66 4. 30.75 5. 33.5 6. 10 7. 110 5 8. 15 24 or 8 8 9. 12 or 23 10. 12 29
1. 64,900 2. 5,250 3. 38,900 4. 52,350 5. 7,437 6. 85.3 7. 236 8. 732 9. 6.62 10. 0.926
1. 408 2. 10 11 2 3. 12 5 or 2 5 4 4. 18 or 2 7 7 5. 14 7 6. 10 7 7. 12 8. 6,707 9. 22.33 10. 20.83
1. 7.58 2. 7.92 3. 8.26 4. 188.25 5. 150.6 6. 768 7. 1,712 3 8. 18 15 or 1 15 25 7 9. 18 or 118 5 10. 30 or 1 25 25
1. 73,900 2. 473.2 3. 5.33 4. 174.3 5. 95 6. 1,350 7. 190 8. 825 9. 138 10. 54
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 273 2. 308 7 3. 12 8 4. 10 or 45 10 5. 3 or 3 13 6. 240 6 7. 12 or 12 5 8. 10 12 or 6 9. 639 10. 91
1. 3.9 2. 13.9 3. 13.93 4. 179.2 5. 174.4 6. 20 7. 10 3 8. 18 15 or 1 15 12 4 9. 15 or 5 1 10. 16 15 or 1 15
1. 89,400 2. 741,000 3. 48,200 4. 51,710 5. 7,128 6. 6,720 7. 825 8. 832 9. 7.65 10. 23.6
1. 506 2. 196 3. 48 or 12 6 4. 10 or 35 28 5. 5 or 5 35 6. 21 7. 56 8. 58 9. 2 10. 4
1. 2.4 2. 12.4 3. 12.37 4. 69.75 5. 70.75 6. 90 7. 30 8. 16 19 9. 30 31 2 10. 35 33 or 1 33
1. 73,400 2. 4,980 3. 61,700 4. 61,290 5. 1,826 6. 98.3 7. 451 8. 618 9. 8.71 10. 0.631
1. 598 9 2. 14 18 4 3. 14 or 1 14 4. 14 or 2 7 5. 60 7 6. 14 or 12 11 7. 12 8. 21,094 9. 9.64 10. 21.75
1. 4.32 2. 4.44 3. 6.8 4. 431.5 5. 172.6 6. 651 7. 272 9 8. 19 20 9. 7 or 2 67 7 10. 18 11 or 1 11
1. 37,100 2. 897.3 3. 7.16 4. 241.3 5. 185 6. 1,550 7. 235 8. 1,350 9. 146 10. 248
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 330 2. 299 3. 58 4. 37 3 5. 17 7 or 2 7 6. 300 8 7. 15 8. 46 or 23 9. 792 10. 99
1. 1.8 2. 1.74 3. 31.74 4. 150.6 5. 156.8 6. 120 7. 12 9 8. 20 3 9. 12 20 or 5 1 10. 21 20 or 1 20
1. 95,200 2. 678,000 3. 17,400 4. 23,480 5. 6,385 6. 9,510 7. 636 8. 916 9. 6.34 10. 94.2
1. 504 2. 276 3. 11 12 9 4. 10 3 5. 23 5 or 4 5 6. 42 6 7. 10 or 35 7 8. 12 9. 6 10. 9
1. 5.6 2. 5.58 3. 55.58 4. 113.25 5. 121.75 6. 60 7. 4 8. 12 13 9. 28 31 10. 32 33
1. 56,100 2. 6,170 3. 17,500 4. 53,210 5. 2,337 6. 73.8 7. 837 8. 772 9. 9.19 10. 0.712
1. 408 8 2. 14 or 47 3. 21 14 or 3 4. 12 6 or 2 5. 48 6. 11 15 7. 13 15 8. 5,236 9. 3.69 10. 31.64
1. 3.68 2. 3.91 3. 8.63 4. 430.5 5. 172.2 6. 2,022 7. 1,026 5 8. 24 19 or 1 19 4 9. 18 or 2 7 7 8 10. 21 13 or 1 13
1. 74,200 2. 642.7 3. 5.61 4. 172.5 5. 285 6. 1,850 7. 315 8. 620 9. 194 10. 336
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
No, both are equal to 360.
No, there are 6 hundreds.
900
6,304
No, one quarter of 2,400 is 600, 300 x 3 = 900.
No, 100,000 – No, Tom has 42, 5,544 90,110 = 9,890. Iko has 31, but Sam has 60.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
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ANSWERS Week 31: Week 31: Grasshopper Shinobi Monday Monday
Week 31: Week 32: Week 32: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 32: Week 33: Week 33: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 33: Grand Master Monday
1. 825 2. 46 or 23 3 3. 21 9 or 2 9 9 1 4. 4 or 2 4 5. 12 9 6. 15 or 35 8 7. 12 or 23 8. 39,536 9. 38.52 10. 8.36
1. 3.84 2. 3.94 3. 4.7 4. 391.5 5. 195.75 6. 1,032 7. 1,778 5 8. 14 9 or 1 9 2 9. 24 or 2 11 11 15 2 10. 13 or 1 13
1. 1,090 2. 5,719 3. 6.86 4. 1,364 5. 245 6. 1,050 7. 370 8. 47 9. 246 10. 430
1. 1,025 2. 450 3. 0.21 4. 38 5. 28 6. 3.47 7. 48 9 8. 18 or 12 5 9. 10 12 or 6 37 1 10. 12 or 3 12
1. 2.57 2. 2.73 3. 5.56 4. 113.25 5. 90.6 6. 1,068 7. 763 1 8. 18 17 or 1 17 1 9. 10 or 1 9 9 5 10. 24 19 or 1 19
1. 593.72 2. 746 3. 192 4. 31 5. 28.4 6. 354.3 7. 2.62 8. 10,100 9. 111,000 10. 27
1. 32 2. 32 3. 4.5 4. 4.5 5. 50 6. 10 7. 83 or 2 23 5 8. 10 12 or 6 9. 18 20 2 10. 26 12 or 2 12
1. 8.74 2. 8.97 3. 45.6 4. 4.56 5. 45.6 6. 4.56 7. 1 8. 1 6 9. 30 8 or 3 8 51 10. 8 or 6 38
1. 0.34 2. 10.6 3. 6.8 4. 1,756 5. 322,000 6. 26.85 7. 21.67 4 8. 39 5 or 7 5 6 9. 18 or 1 12 12 23 3 10. 20 or 120
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 494 8 2. 10 or 45 3 3. 14 11 or 1 11 3 4. 24 or 3 7 7 5. 42 6. 68 or 34 8 7. 16 or 12 8. 86,678 9. 40.32 10. 15.95
1. 6.66 2. 6.87 3. 8.11 4. 178.2 5. 222.75 6. 1,374 7. 1,224 6 8. 15 9 or 1 9 7 9. 24 17 or 1 17 11 10. 24 or 1 13 13
1. 1,190 2. 6,184 3. 8.19 4. 2,045 5. 285 6. 1,650 7. 617 8. 66 9. 490 10. 534
1. 272 2. 190 3. 0.67 4. 42 5. 35 6. 2.92 7. 28 8. 11 20 4 9. 12 15 or 5 3 10. 15 or 2 6 6
1. 11.36 2. 11.41 3. 18.55 4. 196.25 5. 392.5 6. 2,085 7. 2,115 8 8. 25 17 or 1 17 4 9. 18 14 or 1 14 1 10. 20 or 1 19 19
1. 683.82 2. 914 3. 292 4. 33 5. 27 6. 647.1 7. 5.12 8. 20,300 9. 10,100 10. 8
1. 45 2. 45 3. 3.1 4. 3.1 5. 100 6. 20 2 7. 10 4 or 2 4 8. 11 15 1 9. 10 20 or 2 4 10. 24 or 2 10 10
1. 8.36 2. 8.86 3. 34.6 4. 3.46 5. 34.6 6. 3.46 7. 4 8. 2 4 9. 44 10 or 4 10 8 10. 48 or 4 10 10
1. 3.41 2. 19.4 3. 12.4 4. 1,300 5. 149,000 6. 28.57 7. 25.52 1 8. 64 7 or 9 7 9 9. 35 13 or 2 13 10. 96 or 1 36
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 966 9 2. 10 12 1 3. 11 or 1 11 1 4. 10 or 3 3 3 5. 60 7 6. 10 7. 11 16 8. 97,231 9. 55.88 10. 19.62
1. 6.44 2. 6.57 3. 9.13 4. 192.6 5. 481.5 6. 3,752 7. 1,470 1 8. 12 11 or 1 11 18 1 9. 17 or 1 17 9 10. 35 or 2 13 13
1. 3,910 2. 7,834 3. 10.45 4. 3,571 5. 630 6. 2,350 7. 710 8. 45 9. 4 10. 24.4
1. 437 2. 410 3. 0.85 4. 48 5. 38 6. 5.83 7. 35 8. 17 20 2 9. 12 18 or 3 10. 14 or 2 26 6
1. 16.57 2. 16.71 3. 19.54 4. 237.75 5. 190.2 6. 1,757 7. 1,744 5 8. 18 13 or 1 13 28 3 9. 25 or 1 25 17 10. 45 or 1 28 28
1. 1,012.83 2. 785 3. 314 4. 37 5. 32 6. 60.83 7. 1.61 8. 1,110 9. 101 10. 64
1. 72 2. 72 3. 6.7 4. 6.7 5. 200 6. 40 2 7. 14 6 or 2 6 2 8. 12 or 18 3 9. 22 23 21 1 10. 10 or 2 10
1. 8.28 2. 7.68 3. 4.5 4. 0.45 5. 4.5 6. 0.45 7. 9 8. 3 6 9. 40 17 or 2 17 12 10. 80 or 4 17 17
1. 6.721 2. 20.1 3. 14.8 4. 34.9 5. 235,000 6. 166.93 7. 110.96 1 8. 45 4 or 11 4 45 13 9. 16 or 216 3 10. 11 8 or 1 8
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 731 5 2. 10 12 or 6 15 4 3. 11 or 1 11 4 4. 37 or 3 11 11 5. 48 4 6. 10 or 25 5 7. 16 8. 194,667 9. 58.87 10. 25.68
1. 6.44 2. 6.67 3. 10.83 4. 148.6 5. 371.5 6. 1,368 7. 540 2 8. 20 18 or 1 18 36 2 9. 17 or 2 17 6 10. 25 or 1 19 19
1. 5,430 2. 9,128 3. 11.11 4. 5,067 5. 1,025 6. 3,725 7. 11 8. 9 9. 9.4 10. 35.6
1. 704 2. 780 3. 0.92 4. 53 5. 43 6. 2.68 7. 21 8. 13 14 4 9. 16 20 or 5 2 10. 20 or 2 9 9
1. 48.46 2. 48.69 3. 49.73 4. 446.5 5. 178.6 6. 2,115 7. 1,071 3 8. 10 7 or 1 7 30 5 9. 25 or 1 25 2 10. 20 or 1 18 18
1. 1,053.8 2. 101 3. 376 4. 42 5. 44 6. 6.17 7. 25.13 8. 1,011 9. 45.6 10. 125
1. 62 2. 62 3. 5.9 4. 5.9 5. 300 6. 60 2 7. 22 10 or 2 10 5 8. 10 or 12 6 9. 14 17 11 10. 5 or 2 15
1. 13.45 2. 12.75 3. 3.7 4. 0.37 5. 3.7 6. 0.37 7. 16 8. 4 6 9. 66 15 or 4 15 9 10. 99 or 6 15 15
1. 0.567 2. 35.7 3. 16.2 4. 71.7 5. 176,000 6. 124.04 7. 98.67 2 8. 38 4 or 9 4 32 9. 9 or 3 59 9 10. 21 12 or 1 12
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 1,025 9 2. 12 or 34 3 3. 18 15 or 1 15 1 4. 37 12 or 3 12 5. 42 9 6. 10 7. 15 16 8. 222,212 9. 69.31 10. 25.46
1. 6.33 2. 6.56 3. 13.13 4. 130.6 5. 326.5 6. 1,736 7. 2,600 1 8. 18 17 or 1 17 6 9. 25 or 1 19 19 7 10. 30 23 or 1 23
1. 7,030 2. 8,740 3. 14.53 4. 7,503 5. 1,875 6. 4,136 7. 16 8. 21 9. 17.4 10. 40.8
1. 425 2. 560 3. 0.71 4. 56 5. 48 6. 5.62 7. 72 7 8. 12 9 9. 18 20 or 10 1 10. 19 9 or 2 9
1. 12.44 2. 12.59 3. 25.45 4. 207.25 5. 165.8 6. 3,528 7. 1,505 5 8. 12 7 or 1 7 1 9. 24 or 1 23 23 3 10. 21 18 or 1 18
1. 2,300 2. 100.1 3. 401 4. 47 5. 48 6. 6.3 7. 30.42 8. 10,010 9. 101 10. 216
1. 98 2. 98 3. 7.1 4. 7.1 5. 400 6. 70 2 7. 26 12 or 2 12 5 8. 10 12 or 6 6 9. 10 or 35 2 10. 12 5 or 2 5
1. 11.37 2. 12.17 3. 60.7 4. 6.07 5. 60.7 6. 6.07 7. 25 8. 5 12 9. 114 17 or 6 17 16 10. 152 17 or 8 17
1. 1.035 2. 41.2 3. 19.4 4. 94.1 5. 231,000 6. 110.71 7. 97.89 6 8. 34 7 or 4 7 6 9. 28 or 2 11 11 7 10. 21 14 or 1 14
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Yes, 7,000 less than 36,000 is 29,000.
Yes, both are equal to 8,000.
400
14,000
96,000
Yes, 60 x 7 = 420.
Yes, 2.83 - 0.39 = 2.44
Yes, 17 of 630 is 90, and 90 x 3 is 270.
134
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 134
No, 17 of 5,600 is 800, and 800 x 6 is 4,800.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59
ANSWERS Week 34: Week 34: Grasshopper Shinobi Monday Monday
Week 34: Week 35: Week 35: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 35: Week 36: Week 36: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 36: Grand Master Monday
1. 3.4 2. 3.4 3. 71 4. 71 5. 400 6. 70 7. 25 8. 20 9. 135 10. 135
1. 8.13 2. 8.08 3. 56.7 4. 5.67 5. 56.7 6. 5.67 7. 36 8. 6 3 9. 57 9 or 6 9 4 10. 8 9
1. 1,541 2. 482 3. 1,023 4. 0.04 5. 0.95 6. 1.4 7. 5 17 8. 16 4 or 4 2 9. 14 or 17 9 10. 12 or 34
1. 5.4 2. 0.32 3. 1.7 4. 43 5. 67.2 6. 126 7. 10 8. 40 9. 25 10. 40
1. 2.53 2. 3.47 3. 200 4. 100 5. 50 6. 40 7. 121 8. 11 3 9. 28 5 or 5 5 36 10. 5 or 7 15
1. 7,776 2. 241 3. 1,370 4. 0.18 5. 13,034 6. 23.45 4 7. 24 5 or 4 5 15 8. 9 or 1 69 7 9. 12 13 3 10. 10 or 1 10
1. 34.5 2. 0.5 3. 1.5 4. 10.5 5. 16 6. 11 7. 6 34 1 8. 19 6 or 3 6 11 9. 22 or 30 15 2 10. 12 5 or 2 5
1. 62.82 2. 63.18 3. 480 4. 240 5. 120 6. 96 7. 64 8. 4 6 9. 33 9 or 3 9 8 10. 4 9
1. 30,940 2. 734 3. 3,400 4. 40 5. 45.62 6. 7.69 2 7. 18 4 or 4 4 21 8. 9 or 2 39 9. 2 10 12 1 10. 11 10 or 1 10
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 2.2 2. 2.2 3. 25 4. 25 5. 500 6. 90 7. 10 8. 5 9. 146 10. 146
1. 10.25 2. 9.75 3. 80 4. 8 5. 80 6. 8 7. 49 8. 7 8 9. 8 13 10. 10 10 13
1. 173 2. 506 3. 2,300 4. 0.16 5. 0.63 6. 5.6 3 7. 33 6 or 5 6 1 8. 21 or 4 5 5 4 9. 12 or 13 10. 89
1. 7.3 2. 0.19 3. 3.3 4. 57 5. 35.2 6. 184 7. 60 8. 110 9. 15 10. 12
1. 4.64 2. 5.36 3. 400 4. 200 5. 100 6. 80 7. 144 8. 12 6 9. 48 7 or 6 7 3 10. 80 or 11 7 7
1. 7,938 2. 261 3. 1,720 4. 0.28 5. 29,034 6. 45.17 3 7. 27 6 or 4 6 4 8. 10 or 1 6 6 9. 29 8 10. 43 35 or 1 35
1. 60.3 2. 1.4 3. 7.6 4. 11.9 5. 32 6. 20 7. 7 24 8. 4 16 9. 56 10. 95 or 1 45
1. 70.99 2. 71.01 3. 1,000 4. 500 5. 250 6. 200 7. 125 8. 5 1 9. 7 11 7 10. 1011
1. 36,225 2. 807 3. 760 4. 610 5. 61.45 6. 10.66 2 7. 20 9 or 2 9 4 8. 16 or 1 12 12 9. 2 58 2 10. 12 10 or 1 10
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 4.7 2. 4.7 3. 39 4. 39 5. 1,000 6. 250 7. 50 8. 6 9. 213 10. 213
1. 12.17 2. 12.25 3. 78 4. 7.8 5. 78 6. 7.8 7. 64 8. 8 5 9. 10 17 6 10. 12 17
1. 205 2. 715 3. 1,900 4. 0.37 5. 1.73 6. 6.41 6 7. 33 9 or 3 9 1 8. 36 or 7 5 5 1 9. 9 9 3 10. 6 or 1 6
1. 6.1 2. 0.73 3. 8.9 4. 14 5. 61.3 6. 237 7. 210 8. 400 9. 1,000 10. 500
1. 5.32 2. 4.68 3. 500 4. 250 5. 125 6. 100 7. 1 8. 1 2 9. 34 8 or 4 8 5 10. 85 or 10 8 8
1. 19,344 2. 234 3. 3,590 4. 0.75 5. 74,012 6. 75.31 7. 30 5 or 6 8. 18 9 or 2 2 9. 10 or 15 3 10. 13 10 or 1 10
1. 74.6 2. 0.9 3. 12.4 4. 46.3 5. 34 6. 30 3 7. 24 7 or 3 7 2 8. 12 or 2 5 5 6 3 9. 8 or 4 15 10. 7 or 2 17
1. 53.62 2. 54.38 3. 720 4. 360 5. 180 6. 144 7. 1 8. 8 9. 4 15 10. 8 25
1. 47,400 2. 911 3. 49 4. 1,560 5. 72.32 6. 18.95 4 7. 16 6 or 2 6 2 8. 20 or 2 9 9 7 9. 3 8 20 10. 9 or 2 29
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 5.6 2. 5.6 3. 55 4. 55 5. 24 6. 16 7. 20 8. 2 9. 345 10. 345
1. 10.07 2. 10.07 3. 85 4. 8.5 5. 85 6. 8.5 7. 81 8. 9 3 9. 6 11 5 10. 10 11
1. 317 2. 802 3. 964 4. 0.45 5. 2.54 6. 8.41 4 7. 76 9 or 8 9 7 8. 15 or 1 8 8 2 9. 9 22 7 10. 15 or 1 15
1. 1.9 2. 9.1 3. 4.9 4. 62 5. 75.2 6. 289 7. 230 8. 600 9. 150 10. 1
1. 3.09 2. 2.91 3. 440 4. 220 5. 110 6. 88 7. 8 8. 2 1 9. 16 3 or 5 3 1 10. 28 or 9 3 3
1. 31,691 2. 405 3. 8,380 4. 1.54 5. 98,345 6. 98.05 3 7. 27 4 or 6 4 2 8. 12 or 1 10 10 1 9. 15 5 10. 17 12 or 1 12
1. 19.3 2. 0.7 3. 127 4. 84.7 5. 14 6. 15 6 7. 48 7 or 6 7 3 8. 19 or 2 8 8 7 9. 12 18 10. 8 or 2 28
1. 25.52 2. 26.48 3. 60 4. 30 5. 15 6. 12 7. 8 8. 27 9. 8 45 10. 13 15
1. 55,186 2. 832 3. 7.51 4. 256 5. 67.93 6. 22.68 4 7. 22 6 or 3 6 7 8. 16 or 1 9 9 2 9. 3 9 17 5 10. 12 or 112
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 9.8 2. 9.8 3. 61 4. 61 5. 9 6. 18 7. 4 8. 9 9. 128 10. 128
1. 12.47 2. 11.77 3. 78.9 4. 7.89 5. 78.9 6. 7.89 7. 100 8. 10 6 9. 4 13 10. 8 12 13
1. 274 2. 983 3. 1,270 4. 0.16 5. 7.31 6. 9.51 6 7. 48 7 or 6 7 6 8. 20 7 or 2 7 9. 18 1 10. 19 18 or 1 18
1. 2.7 2. 7.3 3. 5.6 4. 74 5. 74.5 6. 347 7. 9 8. 17 9. 6 10. 16
1. 2.37 2. 1.63 3. 240 4. 120 5. 60 6. 48 7. 27 8. 3 1 9. 21 5 or 4 5 3 10. 28 5 or 5 5
1. 36,864 2. 562 3. 11,700 4. 3.17 5. 99,004 6. 101.54 2 7. 20 3 or 6 3 3 8. 18 15 or 1 15 7 9. 18 7 10. 17 10 or 1 10
1. 20.4 2. 13.4 3. 155 4. 30.5 5. 23 6. 13 2 7. 16 7 or 2 7 2 8. 14 6 or 2 6 9 9. 12 or 34 6 10. 18 12 or 1 12
1. 58.45 2. 59.55 3. 600 4. 300 5. 150 6. 120 7. 27 8. 64 9. 11 14 10. 15 34
1. 68,727 2. 705 3. 4.06 4. 1,045 5. 70.56 6. 67.46 3 7. 33 5 or 6 5 7 8. 15 8 or 1 8 9. 4 7 10. 25 9 or 2 9
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Yes, both are equal to 1,000.
No, her answer No, the is 10.78, which difference is is less than 11. 20,000. The answers are 40,000 and 60,000.
No, 706,328 – 805,265 = 98,937.
No, 76 x 8 = 608.
No, 3,600 divided by 1,000 is 3.6.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 135
No, 14,374 – 365 12,000 = 2,374.
No, 15 of 3,500 is 700, and 700 x 3 is 2,100.
135
15/09/2022 09:59
ANSWERS Week 37: Week 37: Grasshopper Shinobi Monday Monday
Week 37: Week 38: Week 38: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 38: Week 39: Week 39: Grand Master Grasshopper Shinobi Monday Monday Monday
Week 39: Grand Master Monday
1. 9.8 2. 45 3. 14 4. 20 5. 299 6. 23 7. 3 46 8. 2 23 9. 13 15 3 10. 18 15 or 1 15
1. 49.68 2. 25.82 3. 24 4. 4.8 5. 9.6 6. 1 7. 1 8. 1 9. 6 14 10. 16 14
1. 15,651 2. 632 3. 286,510 4. 591,109 5. 8.95 6. 40.67 7. 325.3 8. 280 3 9. 39 4 or 9 4 27 7 10. 20 or 1 20
1. 34.2 2. 54 3. 178,566 4. 36,626 5. 962 6. 64 2 7. 18 4 or 4 4 8. 2 9. 14 15 10. 76 or 1 16
1. 6.8 2. 8.79 3. 35 4. 3.5 5. 0.35 6. 36 7. 216 8. 6 9. 7 27 10. 9 57
1. 36.7 2. 0.56 3. 9 4. 1,750 5. 700,000 6. 4,305 7. 2,368 8. 774 9. 571 10. 60,000
1. 0.3 2. 4.8 3. 47.55 4. 14.77 5. 1,224 6. 87 7. 7 24 7 8. 2 10 9 9. 10 2 10. 18 4 or 4 4
1. 56.4 2. 35.79 3. 11 4. 1.1 5. 0.11 6. 121 7. 1,331 8. 11 9 9. 9 11 3 10. 12 11
1. 32 2. 0.06 3. 8.43 4. 6.4 5. 32,000 6. 5,049 7. 8,262 8. 3,892 9. 632 10. 8,000
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday
1. 13.5 2. 160 3. 30 4. 10 5. 1,219 6. 32 7. 4 46 8. 3 15 9. 14 15 4 10. 28 8 or 3 8
1. 48.49 2. 68.55 3. 18 4. 9 5. 3.6 6. 4 7. 8 8. 2 9. 5 13 10. 9 13
1. 22,827 2. 1896 3. 399,664 4. 637,174 5. 6.27 6. 66.04 7. 231.9 8. 680 4 9. 44 5 or 8 5 3 10. 12
1. 20.6 2. 71 3. 298,548 4. 44,239 5. 1,428 6. 54 7. 7 24 8. 3 49 9. 19 30 10. 75 or 1 25
1. 45.6 2. 32.56 3. 25 4. 12.5 5. 10 6. 49 7. 343 8. 7 9. 10 57 10. 14 27
1. 71.3 2. 0.43 3. 1 4. 2,370 5. 500,000 6. 3,702 7. 2,368 8. 1,505 9. 618 10. 90,000
1. 1.4 2. 16 3. 47.56 4. 3.95 5. 629 6. 96 7. 9 13 9 8. 1 10 9. 18 20 3 10. 18 5 or 3 5
1. 7.9 2. 3.67 3. 200 4. 80 5. 100 6. 144 7. 1,728 8. 12 9. 26 18 10. 31 58
1. 90 2. 0.07 3. 6.47 4. 5.1 5. 21,000 6. 8,038 7. 16,884 8. 1,917 9. 949 10. 6,000
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
Wednesday
1. 43 2. 320 3. 200 4. 120 5. 968 6. 45 7. 7 8. 2 16 9. 56 10. 83 or 2 23
1. 43.46 2. 77.8 3. 15 4. 1.5 5. 0.15 6. 9 7. 27 8. 3 9. 25 15 10. 26 25
1. 28,448 2. 507 3. 524,526 4. 204,565 5. 18.96 6. 80.04 7. 310.5 8. 380 9. 30 3 or 10 10. 11 12
1. 43.2 2. 67 3. 378,543 4. 55,192 5. 2,142 6. 63 7. 6 23 8. 2 49 9. 12 14 4 10. 10 6 or 1 6
1. 7.8 2. 7.97 3. 16 4. 1.6 5. 0.16 6. 64 7. 512 8. 8 9. 7 35 10. 11 25
1. 80.4 2. 0.17 3. 7 4. 1,930 5. 160,000 6. 1,730 7. 3,796 8. 2,280 9. 728 10. 80,000
1. 7.2 2. 20 3. 61.79 4. 9.6 5. 924 6. 104 7. 4 48 8. 4 13 8 9. 10 9 10. 20 11 or 1 11
1. 47.4 2. 65.3 3. 4 4. 0.4 5. 0.04 6. 25 7. 216 8. 8 9. 8 28 10. 9 58
1. 134 2. 0.84 3. 5.005 4. 6.8 5. 30,000 6. 7,274 7. 20,328 8. 2,847 9. 1,573 10. 5,000
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
Thursday
1. 53.9 2. 105 3. 110 4. 60 5. 782 6. 65 7. 2 23 8. 1 35 7 9. 12 10. 85 or 1 35
1. 72.36 2. 29.94 3. 40 4. 20 5. 16 6. 16 7. 64 8. 4 9. 25 17 10. 28 27
1. 37,089 2. 649 3. 713,542 4. 207,151 5. 10.63 6. 94.32 7. 531.7 8. 500 2 9. 26 3 or 8 3 5 10. 15 or 1 10 10
1. 31.7 2. 87 3. 467,057 4. 22,175 5. 925 6. 74 7. 10 59 8. 3 79 8 9. 10 2 10. 20 6 or 3 6
1. 26.6 2. 75.65 3. 45 4. 22.5 5. 18 6. 81 7. 729 8. 9 9. 7 39 10. 9 79
1. 91.9 2. 1.05 3. 5 4. 9,450 5. 420,000 6. 2,360 7. 6,237 8. 3,375 9. 793 10. 80,000
1. 9.8 2. 35 3. 37.99 4. 3.3 5. 910 6. 124 7. 6 14 8. 3 16 9 9. 18 20 or 10 3 10. 12 or 1 9 9
1. 7.4 2. 9.75 3. 300 4. 150 5. 120 6. 49 7. 1,331 8. 3 9. 9 35 10. 11 15
1. 162 2. 0.92 3. 7.38 4. 1.25 5. 18,000 6. 8,231 7. 25,854 8. 4,560 9. 2,537 10. 9,000
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
Friday
1. 10.9 2. 260 3. 15 4. 48 5. 1,302 6. 75 7. 3 35 8. 2 9. 19 20 10. 73 or 2 13
1. 91.25 2. 56.7 3. 24 4. 2.4 5. 0.24 6. 25 7. 125 8. 5 9. 5 15 10. 7 45
1. 22,856 2. 733 3. 137,686 4. 11,554 5. 53.57 6. 101.31 7. 672.1 8. 960 9. 75 3 or 25 5 10. 11 6 or 1 6
1. 90.7 2. 47 3. 572,435 4. 62,191 5. 988 6. 87 7. 2 28 7 8. 1 10 9. 16 18 4 10. 24 5 or 4 5
1. 6.6 2. 8.64 3. 8 4. 0.8 5. 0.08 6. 100 7. 1,000 8. 10 1 9. 8 10 7 10. 8 10
1. 105.6 2. 0.06 3. 8 4. 7,130 5. 320,000 6. 7,382 7. 7,221 8. 4,476 9. 854 10. 80,000
1. 10.4 2. 56 3. 62.71 4. 12.6 5. 855 6. 109 7. 11 23 8. 2 15 9. 17 20 3 10. 15 6 or 2 6
1. 74.3 2. 68.74 3. 134 4. 13.4 5. 1.34 6. 64 7. 64 8. 9 7 9. 7 13 10. 10 10 13
1. 184 2. 0.17 3. 8.31 4. 3.24 5. 54,000 6. 9,043 7. 38,836 8. 3,415 9. 3,533 10. 8,000
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Ninja Challenge
Yes. 7.9 + 14.56 No, because = 8 + 14.46 = 401,384 + 22.46. 313,394 = 714,778.
No, 717,758 + 190,327 = 908,085.
No, 34.53– 22.3 No, 4,000 x 8 = = 12.23. 32,000.
18,900
No, 9,000 x 2 = 18,000, which is 2,000 more than 16,000.
Yes, 640 divided by 10 = 6.4 and 8 – 1.6 = 6.4.
136
Arithmetic_Ninja_For_Ages_9-10_9781801990677_app.indd 136
No, 19 of 72,000 is 8,000, and 8,000 x 8 is 64,000.
Arithmetic Ninja 9–10 © Andrew Jennings, 2022
15/09/2022 09:59