Subtraction Within 10 and 20

Year 1 subtraction covers taking away within 10 and then within 20. Children learn to take away objects from a group, count what is left, and write number sentences like 9 - 4 = 5.

Children encounter subtraction as both "taking away" (I had 8 sweets and ate 3, how many left?) and "finding the difference" (Tom has 5, Sara has 9 -- how many more does Sara have?). Both concepts are important and appear throughout KS1 assessments.

They also learn the link between addition and subtraction: if 4 + 5 = 9, then 9 - 5 = 4. This inverse relationship helps children check their own work and builds flexible thinking.

Subtraction is essential for problem solving, money skills, measurement and telling the time. Children who struggle with basic subtraction often find word problems and multi-step questions very difficult later on.

Understanding subtraction as the inverse of addition gives children a powerful checking tool -- they can verify their answers independently, which builds confidence and mathematical resilience.

1. 1

   Use physical objects first: 'Here are 7 bricks. Take away 3. How many left?'

2. 2

   Practise 'counting back' on a number line from the larger number.

3. 3

   Connect subtraction to addition: 'If 3 + 4 = 7, what is 7 - 4?'

4. 4

   Use story problems at mealtimes: 'There were 10 chips, you ate 4 -- how many left?'

5. 5

   Avoid saying subtraction is 'hard'. Frame it as 'the opposite of adding, which you already know'.

6. 6

   Play board games that involve moving backwards along a track.