Master Mental Math: Addition and Subtraction Strategies for Year 5

Question 1

The 'count on' strategy is used to solve:

Accepted Answer

14 + 6

Answer

25 - 13

Answer

37 + 23

Answer

49 - 18

Question 2

When adding or subtracting, what strategy involves breaking a number into smaller parts?

Accepted Answer

Partitioning

Answer

Number bonds

Answer

Compensation

Answer

Estimation

Question 3

When adding 25 and 37 mentally using partitioning, what is the first step?

Accepted Answer

Separate 25 into 20 and 5

Answer

Separate 37 into 30 and 7

Answer

Add the tens digits first

Answer

Add the ones digits first

Question 4

Which strategy can be used to add 9 to 43 mentally?

Accepted Answer

Compensation

Answer

Number bonds

Answer

Partitioning

Answer

Expanded form

Question 5

Which of these methods can you use to work out 24 - 7 using compensation?

Accepted Answer

Add 1 to 7 and subtract 1 from 24

Answer

Subtract 1 from 7 and add 1 to 24

Answer

Multiply 7 by 2 and subtract from 24

Answer

Divide 24 by 7 and subtract 1

Question 6

Use compensation to solve: 46 - 19

Accepted Answer

45 - 20

Answer

47 - 20

Answer

46 - 21

Answer

45 - 18

Question 7

When finding the difference between 45 and 19, which mental subtraction strategy would be most efficient?

Accepted Answer

Compensation

Answer

Partitioning

Answer

Number Line

Answer

Rounding

Question 8

To solve the equation 27 + __ = 35 using compensation, which equation should be used?

Accepted Answer

27 + 10 - 5 = 35

Answer

27 + 5 = 35

Answer

35 - 27 = 8

Answer

35 - 10 + 5 = 27

Question 9

Using mental subtraction partitioning, what is the difference between 68 and 34?

Accepted Answer

64

Answer

34

Answer

68

Answer

102

Question 10

Which of the following is NOT a mental addition strategy?

Accepted Answer

Number Line

Answer

Bridging

Answer

Counting On

Answer

Rounding

Question 11

What is 54 added to 27?

Accepted Answer

81

Answer

71

Answer

91

Answer

101

Question 12

Which number sentence shows 23 partitioned into tens and ones?

Accepted Answer

20 + 3

Answer

23 + 0

Answer

30 + 3

Question 13

Which method is best for finding the difference between 72 and 35?

Accepted Answer

Subtracting tens and ones

Answer

Counting up

Answer

Compensation

Question 14

Which strategy involves breaking a number into smaller parts to make calculations easier?

Accepted Answer

Partitioning

Answer

Number bonds

Answer

Estimation

Question 15

Find the difference between 85 and 57 using compensation.

Accepted Answer

28

Answer

27

Answer

29

Question 16

Which of the following is NOT a way to add numbers mentally?

Accepted Answer

Long multiplication

Answer

Counting up

Answer

Number bonds

Question 17

What number is 10 more than 67?

Accepted Answer

87

Answer

57

Answer

77

Question 18

To solve 24 + 16 - 7, use the compensation strategy.

Accepted Answer

33

Answer

37

Answer

29

Question 19

Which number is 20 less than 83?

Accepted Answer

53

Answer

63

Answer

73

Question 20

Which mental addition strategy involves adjusting one number to make it easier to calculate?

Accepted Answer

Compensation

Answer

Number bonds

Answer

Partitioning

Answer

Rounding

Question 21

When subtracting mentally, which strategy involves breaking a number into parts to help calculate?

Accepted Answer

Partitioning

Answer

Number bonds

Answer

Compensation

Answer

Rounding

Question 22

Which addition problem below can be solved using the compensation strategy?

Accepted Answer

15 + 6

Answer

23 - 8

Answer

12 + 9

Answer

18 - 5

Question 23

What is the difference between 53 and 19?

Accepted Answer

34

Answer

24

Answer

44

Answer

54

Question 24

Which of the following is NOT a mental addition strategy?

Accepted Answer

Carrying

Answer

Number bonds

Answer

Compensation

Answer

Partitioning

Question 25

You have 47 pencils. You want to give 13 pencils to your classmate. Which mental subtraction strategy will help you find out how many pencils you will have left?

Accepted Answer

Subtract 10 then subtract 3

Answer

Subtract 13 from 50 then add 3

Answer

Subtract 10 then add 7

Answer

Halve 47 then halve 13 and subtract the results

Question 26

Which of the following is NOT a mental subtraction strategy?

Accepted Answer

Regrouping

Answer

Compensation

Answer

Partitioning

Answer

Number bonds

Question 27

Which of the following is not a strategy for mental addition?

Accepted Answer

Multiplication

Answer

Number bonds

Answer

Compensation

Answer

Partitioning

Question 28

What is the difference between 49 and 26?

Accepted Answer

21

Answer

23

Answer

25

Question 29

A fruit seller has 28 apples and sells 10 of them. How many apples does the seller have left?

Accepted Answer

18

Answer

10

Answer

28

Question 30

What mental addition and subtraction strategy involves using known number bonds to calculate quickly?

Accepted Answer

Number bonds

Answer

Compensation

Answer

Partitioning

Question 31

Calculate 24 + 17 using number bonds:

Accepted Answer

20 + 15 + 2 = 37

Answer

20 + 20 = 40

Answer

30 + 10 = 40

Question 32

Partition 45 into two parts to subtract 13 using partitioning:

Accepted Answer

30 and 15

Answer

40 and 5

Answer

25 and 20

Question 33

Which of these can be solved mentally using mental addition?

Accepted Answer

25 + 18

Answer

123 + 456

Answer

547 - 234

Question 34

True or False: Compensation can only be used for addition.

Accepted Answer

False

Answer

True

Question 35

Which strategy would be most effective for subtracting 9 from 67?

Accepted Answer

Compensation

Answer

Number bonds

Answer

Partitioning

Question 36

Partition 36 into three equal parts:

Accepted Answer

12, 12, 12

Answer

10, 10, 16

Answer

9, 9, 18

Question 37

Calculate the value of 32 + 15 - 9 using mental addition and subtraction strategies.

Accepted Answer

38

Answer

48

Answer

28

Answer

58

Question 38

Which of the following is NOT a benefit of utilizing mental math strategies?

Accepted Answer

Increased reliance on calculators

Answer

Reduced cognitive load

Answer

Enhanced number sense

Answer

Improved problem-solving skills

Question 39

Identify the number bond that can be utilized for mental subtraction:

Accepted Answer

10 - 5 = 5

Answer

15 + 5 = 20

Answer

20 - 10 = 30

Answer

25 + 5 = 30

Question 40

Identify the key component of effective mental math instruction:

Accepted Answer

Regular practice and scaffolding

Answer

Sole reliance on mental math strategies

Answer

Focus on memorization of facts

Answer

Limited use of concrete materials

Question 41

To add 24 and 37 using number bonds, we break them down into smaller numbers that add up to 10. For example, 24 can be split into 20 and 4, and 37 can be split into 30 and 7. What is the result of adding 20, 4, 30, and 7?

Accepted Answer

61

Answer

59

Answer

63

Question 42

A library has 35 books on the shelf. If 12 more books are added, how many books will there be in total?

Accepted Answer

47

Answer

57

Answer

37

Answer

23

Question 43

Which of these strategies is NOT used for mental addition and subtraction?

Accepted Answer

Rounding

Answer

Partitioning

Answer

Compensation

Answer

Number Bonds

Question 44

Which strategy would be the easiest for subtracting 99 from 205 in your head?

Accepted Answer

Compensation

Answer

Partitioning

Answer

Number Bonds

Answer

Expanded Form

Question 45

Use a number line to find the sum of 34 and 29. What's the answer?

Accepted Answer

63

Answer

53

Answer

73

Answer

83

Question 46

Which of these is NOT a way to subtract numbers in your head?

Accepted Answer

Long division

Answer

Number Bonds

Answer

Compensation

Answer

Partitioning

Question 47

Which mental addition strategy involves splitting numbers into smaller parts?

Accepted Answer

Partitioning

Answer

Compensation

Answer

Number Bonds

Question 48

What's the easiest way to add 75 and 25 in your head?

Accepted Answer

Think of 25 as 25 + 0. Then, 75 + 25 is the same as (75 + 25) + 0, which is 100.

Answer

Break 75 into 70 + 5, and 25 into 20 + 5. Then add them together: 70 + 20 + 5 + 5 = 90 + 10 = 100.

Answer

Change 75 to 80, add 25, then take away 5.  80 + 25 = 105, and 105 - 5 = 100.

Question 49

Which one is NOT a trick for subtracting in your head?

Accepted Answer

Using a calculator

Answer

Counting backwards

Answer

Making the numbers easier to work with

Answer

Adding to make the number easier

Question 50

Let's subtract 18 from 53 in our heads using the 'making it easier' trick. How do we do it?

Accepted Answer

Change 18 to 20, subtract from 53 (which is 33), then add 2 back: 33 + 2 = 35

Answer

Take away 10 from 53 (which is 43), then take away 8: 43 - 8 = 35

Answer

Take 18 away from 50 (which is 32), then add 3: 32 + 3 = 35

Answer

Subtract 10 from 53 (which is 43), then subtract another 10 (which is 33), then add 2: 33 + 2 = 35

Question 51

You want to buy a toy for £47, but you only have £32. How much more money do you need?

Accepted Answer

£15

Answer

£13

Answer

£17

Answer

£20

Question 52

What number should go in the blank: 35 + ___ = 80?

Accepted Answer

45

Answer

50

Answer

40

Answer

55

Question 53

What's the smartest way to add 48 and 52 in your head?

Accepted Answer

Round them both to 50. 50 + 50 is 100.

Answer

Start at 48 and count up 52 times: 48 + 1 + 1 + 1... + 52 = 100

Answer

Add 2 to 48 (which makes 50), then add 52 (which is 102), then take away 2: 102 - 2 = 100

Answer

Split 48 into 40 + 8 and 52 into 50 + 2.  Add the parts together: 40 + 50 + 8 + 2 = 90 + 10 = 100

Question 54

You have 67 sweets and eat 29. How many sweets are left?

Accepted Answer

38

Answer

36

Answer

48

Question 55

Let's subtract 37 from 96 in our heads using the 'making tens' trick. How do we do it?

Accepted Answer

Take away 4 from 96 (which is 92), then 3 from 92 (which is 89), then 30 from 89 (which is 59).

Answer

Take away 30 from 96 (which is 66), then take away 7: 66 - 7 = 59

Answer

Take away 10 from 96 (which is 86), then take away 27: 86 - 27 = 59

Answer

Take away 30 from 96 (which is 66), then take away 10 (which is 56), then take away 7: 56 - 7 = 59

Question 56

What's the best way to add 63 and 37 in your head?

Accepted Answer

Think of 37 as 37 + 0. Then, 63 + 37 is the same as (63 + 37) + 0, which is 100.

Answer

Start at 63 and count up 37 times: 63 + 1 + 1 + 1... + 37 = 100

Answer

Add 3 to 63 (which is 66), then add 37 (which is 103), then take away 3: 103 - 3 = 100

Question 57

You have 84 pencils and give away 35. How many are left?

Accepted Answer

49

Answer

47

Answer

51

Answer

59