*This quiz addresses the requirements of the National Curriculum KS1 Maths and Numeracy for children aged 6 and 7 in year 2. Specifically this quiz is aimed at the section dealing with knowing number facts to 100. *

Knowing addition and subtraction facts by heart means being able to quickly know the pairs of numbers which make a total of 100, as well as the associated subtraction facts. This knowledge of the number pairs, or bonds, to 100 can be linked to knowing the number pairs to 10. For example, if you know that 3 + 7 = 10, then you may realise that 30 + 70 = 100.

Question 1

Which of the following is true?

10 - 80 = 20

100 - 20 = 80

80 - 20 = 100

20 - 80 = 100

100 - 80 = 20 is the other subtraction fact for these numbers

Question 2

Which 'family' of facts is incorrect?

10 + 90 = 100

90 + 10 = 100

100 - 90 = 10

100 - 10 = 90

90 + 10 = 100

100 - 90 = 10

100 - 10 = 90

20 + 80 = 100

80 + 20 = 100

100 - 20 = 80

100 - 80 = 20

80 + 20 = 100

100 - 20 = 80

100 - 80 = 20

60 + 50 = 100

50 + 60 = 100

100 - 60 = 50

100 - 50 = 60

50 + 60 = 100

100 - 60 = 50

100 - 50 = 60

30 + 70 = 100

70 + 30 = 100

100 - 30 = 70

100 - 70 = 30

70 + 30 = 100

100 - 30 = 70

100 - 70 = 30

60 + 50 = 110, so all the other facts must be incorrect too

Question 3

If you know that 2 + 8 = 10, what else do you know?

20 + 80 = 100

12 + 18 = 20

2 + 80 = 100

8 + 20 = 100

80 + 20 would also give 100

Question 4

Which of these three other facts go with 30 + 70 = 100?

100 + 30 = 70

70 - 30 = 100

30 - 70 = 100

70 - 30 = 100

30 - 70 = 100

30 + 30 = 70

70 - 30 = 100

30 - 100 = 70

70 - 30 = 100

30 - 100 = 70

70 + 70 = 100

30 +30 = 100

100 - 100 = 30

30 +30 = 100

100 - 100 = 30

70 + 30 = 100

100 - 30 = 70

100 - 70 = 30

100 - 30 = 70

100 - 70 = 30

For the subtraction facts, the largest number should be at the beginning

Question 5

Which one of the following number pairs do not add up to give 100?

100 + 0

90 + 10

60 + 40

20 + 18

20 + 18 = 38

Question 6

Which number fact is incorrect?

6 + 40 = 100

60 + 40 = 100

40 + 60 = 100

100 - 60 = 40

6 + 40 = 46!

Question 7

Which number is missing: 10 + ? = 100

100

9

90

10

10 + 90 = 100, so 90 + 10 = 100 also

Question 8

Which three pairs of numbers all add up to 100?

20 + 80

10 + 90

50 + 50

10 + 90

50 + 50

10 + 80

20 + 18

60 + 4

20 + 18

60 + 4

12 + 18

20 + 8

100 + 10

20 + 8

100 + 10

40 + 6

50 + 5

10 + 9

50 + 5

10 + 9

All the others give different totals

Question 9

Which of the following is true?

6 + 4 = 10, so 60 + 4 = 100

6 + 4 = 10, so 60 + 40 = 100

6 + 4 = 10, so 16 + 14 = 100

6 + 4 = 10, so 6 + 40 = 100

60 + 40 gives an answer which is ten times bigger than 6 + 4

Question 10

Which 'family' of facts is incorrect?

35 + 65 = 100

65 + 35 = 100

100 - 35 = 65

100 - 65 = 35

65 + 35 = 100

100 - 35 = 65

100 - 65 = 35

25 + 75 = 100

75 + 25 = 100

100 - 25 = 75

100 - 75 = 25

75 + 25 = 100

100 - 25 = 75

100 - 75 = 25

15 + 85 = 100

85 + 15 = 100

100 - 85 = 15

100 - 15 = 85

85 + 15 = 100

100 - 85 = 15

100 - 15 = 85

65 + 45 = 100

45 + 65 = 100

100 - 65 = 45

100 - 45 = 65

45 + 65 = 100

100 - 65 = 45

100 - 45 = 65

65 + 45 = 110, so all the other facts must be incorrect too