 If 12 + 8 = 20 then 20 - 12 = 8!

# Year 2 Calculation - Addition and Subtraction Facts to 20

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 20.

Knowing addition and subtraction facts (or number facts) to 20 by heart means being able to quickly know the pairs of numbers which make a total of twenty, as well as the associated subtraction facts. For example, if you know that 13 + 7 = 20, then you should also recognise that 20 - 13 = 7 or 20 - 7 = 13.

Question 1
Which three pairs of numbers all add up to 20?
19 + 1
17 + 3
5 + 15
12 + 9
11 + 7
3 + 16
7 + 20
6 + 12
7 + 19
4 + 12
16 + 8
20 + 1
All the others add up to different numbers
Question 2
Which 'family' of facts is incorrect?
7 + 13 = 20
13 + 7 = 20
20 - 13 = 7
20 - 7 = 13
8 + 12 = 20
12 + 8 = 20
20 - 8 = 12
20 - 12 = 8
9 + 11 = 20
11 + 9 = 20
20 - 11 = 9
20 - 9 = 11
4 + 14 = 20
14 + 4 = 20
20 - 4 = 14
20 - 14 = 4
14 + 4 = 18, so all the other facts must be incorrect too
Question 3
Which of the following is true?
12 - 20 = 8
20 - 2 = 18
8 + 20 = 12
18 + 20 = 2
20 - 18 = 2 is the other subtraction fact for these numbers
Question 4
Which number is missing: 17 + ? = 20
5
3
7
9
17 + 3 = 20 and so 3 + 17 = 20 also
Question 5
Which of the following pairs of number do not add up to give 20?
9 + 11
2 + 18
16 + 5
20 + 0
16 + 5 = 21
Question 6
Which 'family' of facts is incorrect?
2 + 18 = 20
18 + 2 = 20
20 - 18 = 2
20 - 2 = 18
16 + 5 = 20
5 + 16 = 20
20 - 16 = 5
20 - 5 = 16
5 + 15 = 20
15 + 5 = 20
20 - 5 = 15
20 - 15 = 5
10 + 10 = 20
20 - 10 = 10
16 + 5 = 21, not 20 so all the other facts must be incorrect too
Question 7
Which of the following is true?
2 + 18 = 20 so 20 + 18 = 2
2 + 18 = 20 so 18 + 2 = 20
2 + 18 = 20 so 20 + 2 = 18
2 + 18 = 20 so 18 + 20 = 2
Adding the two smaller numbers in any order gives the larger number
Question 8
Which number fact is incorrect?
11 + 9 = 20
9 + 11 = 20
20 - 9 = 11
11 - 20 = 9
11 - 20 gives a negative answer of -9!
Question 9
If you know that 14 + 6 = 20, what else do you know?
20 + 14 = 6
20 - 14 = 6
14 - 20 = 6
6 - 14 = 20
You would also know that 20 - 6 = 14
Question 10
Which three other facts go with 16 + 4 = 20?
20 + 16 = 4
20 + 4 = 16
16 - 20 = 4
16 - 20 = 4
4 - 20 = 16
20 + 16 = 4
4 + 16 = 20
16 - 4 = 20
4 - 16 = 20
4 + 16 = 20
20 - 16 = 4
20 - 4 = 16
For the subtraction facts, the largest number should be at the beginning
Author:  Angela Smith