# Number Logic Practice 2

In this practice exercise, students will identify a rule which is used to make a number and apply this rule to find a missing number.

Key stage:  KS 2

Curriculum topic:   Exam-Style Questions: Verbal Reasoning

Curriculum subtopic:   Exam-Style Questions: Number Logic

Difficulty level:

### QUESTION 1 of 10

If you are unsure of an answer, move on to the next question.

You should come back to questions you found difficult at the end if you have time.

Let's try one together as a reminder:

We need to work out how the numbers on the outside of the brackets create the numbers on the inside of the brackets and then apply the same rule to the third set of brackets.

10 (23) 3        5 (16) 6        2 ( _ ) 5

First, we need to find a way to make 23 using 10 and 3.

If we add 10 and 3 together we get 13.

Then, if we add another lot of 10, we get to 23.

So the rule could be: add the two outside numbers and then add the first number again.

Apply to the second set of numbers: 5 + 5 + 6 = 16.

We’ve found the rule.

Then we use the rule to work out the missing number in the final set: 2 + 2 + 5 = 9.

The missing number is 9.

Now it's time to begin this practice exercise.

Good luck!

Look at the numbers below.

4 (18) 10       20 (48) 8      19 (?) 7

What is the mystery number?

43

44

45

46

47

Look at the numbers below.

3 (90) 9       5 (146) 11          6 (?) 4

What is the mystery number?

51

52

53

54

55

Look at the numbers below.

8 (27) 1        2 (21) 5        5 (?) 6

What is the mystery number?

30

33

36

39

42

Look at the numbers below.

21 (22) 65        45 (25) 95        16 (?) 58

What is the mystery number?

19

20

21

22

23

Look at the numbers below.

56 (32) 24        93 (55) 38        72 (?) 40

What is the mystery number?

22

32

42

52

62

Look at the numbers below.

30 (48) 9        12 (42) 15        14 (?) 13

What is the mystery number?

37

38

39

40

41

Look at the numbers below.

3 (13) 4          6 (43) 7          9 (?) 10

What is the mystery number?

91

81

85

95

92

Look at the numbers below.

10 (9) 50        8 (12) 64        6 (?) 72

What is the mystery number?

13

14

15

16

17

Look at the numbers below.

9 (18) 4        6 (15) 5        4 (?) 12

What is the mystery number?

21

22

23

24

25

Look at the numbers below.

8 (44) 3        3 (20) 2        7 (?) 1

What is the mystery number?

32

36

40

44

48

• Question 1

Look at the numbers below.

4 (18) 10       20 (48) 8      19 (?) 7

What is the mystery number?

45
EDDIE SAYS
Look at the first set of numbers: 4 (18) 10 The number in the middle is bigger than the outside numbers so we are adding or multiplying. 4 + 10 = 14 14 + 4 = 18 The rule is 'left number + right number + left number'. Apply to second set to check: 20 (48) 8 20 (left number) + 8 (right number) + 20 (left number) = 48 (middle number). Work out the mystery number: 19 + 7 + 19 = 45
• Question 2

Look at the numbers below.

3 (90) 9       5 (146) 11          6 (?) 4

What is the mystery number?

52
EDDIE SAYS
The rule is 'left number squared + right number squared'. Apply to first set: 3 (90) 9 3² (9) + 9² (81) = 90 Apply to second set: 5 (146) 11 5² (25) + 11² (121) = 146 Work out the mystery number: 6 (?) 4 6² (36) + 4² (16) = 52
• Question 3

Look at the numbers below.

8 (27) 1        2 (21) 5        5 (?) 6

What is the mystery number?

33
EDDIE SAYS
Look at the first set of numbers: 8 (27) 1 How many 3s go into 27? There are nine 3s in 27 and can we make 9 with the outside numbers? Yes we can, 8 + 1 = 9. The rule is '(left number + right number) x 3'. Apply to second set: 2 (21) 5 2 (left number) + 5 (right number) = 7 7 x 3 = 21 Work out the mystery number: 5 (?) 6 5 + 6 = 11 11 x 3 = 33
• Question 4

Look at the numbers below.

21 (22) 65        45 (25) 95        16 (?) 58

What is the mystery number?

21
EDDIE SAYS
The numbers inside the brackets are smaller than at least one of the outside numbers, we are subtracting or dividing. Look at the first set: 21 (22) 65 65 (right number) - 21 (left number) = 44 How can we get from 44 to the middle number 22? 44 ÷ 2 = 22 Our rule is '(right number - left number) ÷ 2' Apply to second set of numbers: 45 (25) 95 95 (right number) - 45 (left number) = 50 50 ÷ 2 = 25 Work out mystery number: 16 (?) 58 58 - 16 = 42 42 ÷ 2 = 21
• Question 5

Look at the numbers below.

56 (32) 24        93 (55) 38        72 (?) 40

What is the mystery number?

32
EDDIE SAYS
The rule is 'left number - right number'. Work out mystery number: 72 (left number) - 40 (right number) = 32
• Question 6

Look at the numbers below.

30 (48) 9        12 (42) 15        14 (?) 13

What is the mystery number?

40
EDDIE SAYS
Find rule: 30 (48) 9 30 + 9 = 39 The rule is 'left number + right number + right number'. Apply to second set: 12 (42) 15 12 (left number) + 15 (right number) + 15 (right number) = 42 Work out mystery number: 14 (?) 13 14 + 13 + 13 = 40
• Question 7

Look at the numbers below.

3 (13) 4          6 (43) 7          9 (?) 10

What is the mystery number?

91
EDDIE SAYS
The rule is 'left number squared + right number'. Apply to first set: 3 (13) 4 3² + 4 = 13 Apply to second set: 6 (43) 7 6² + 7 = 43 Work out mystery number: 9 (?) 10 9² (81) + 10 = 91
• Question 8

Look at the numbers below.

10 (9) 50        8 (12) 64        6 (?) 72

What is the mystery number?

16
EDDIE SAYS
Look at the first set: 10 (9) 50 50 ÷ 10 = 5 How can we get to the middle number 9 from 5? We add 4. The rule is '(right number ÷ left number) + 4' Apply to second set: 8 (12) 64 64 ÷ 8 = 8 8 + 4 = 12. Work out mystery number: 6 (?) 72 72 ÷ 6 = 12 12 + 4 = 16
• Question 9

Look at the numbers below.

9 (18) 4        6 (15) 5        4 (?) 12

What is the mystery number?

24
EDDIE SAYS
Look at first set: 9 (18) 4 9 x 4 = 36 36 ÷ 2 = 18 The rule is '(left number x right number) ÷ 2'. Apply to second set: 6 (15) 5 6 x 5 = 30 30 ÷ 2 = 15 Work out mystery number: 4 (?) 12 4 x 12 = 48 48 ÷ 2 = 24
• Question 10

Look at the numbers below.

8 (44) 3        3 (20) 2        7 (?) 1

What is the mystery number?

32
EDDIE SAYS
The numbers inside the brackets are all part of the 4 times table. 8 (44) 3 4 goes into 44, 11 times. We can make 11 with the two outside numbers: 8 + 3 = 11 The rule is '(left number + right number) x 4'. Apply to second set: 3 (20) 2 3 + 2 = 5 5 x 4 = 20 Work out the mystery number: 7 (?) 1 7 + 1 = 8 8 x 4 = 32
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