Subtraction needs to be seen as the reverse process of addition.
Stage 1
Subtraction with numbers below 10
Practice 1
Example 7 – 4
- 4 is made from 2 and 2. Removing 2 coins from 7 leaves 5 and taking away another 2 leaves 3
- Take 4 coins from the “5” block leaving 1. Thus 1 + 2 = 3
Either method is possible. Essentially we are using 5 as a point to work from.
Stage 2
Subtraction with numbers above 10
Practice 2
Example 13 – 8
- Take 8 coins from the “10” block leaving 2. Thus 2 + 3 = 5
Example 13 – 5
- Take 5 coins from the “5” block leaving 5 and 3
- 5 is made from 3 and 2.Removing 3 coins from 13 leaves 10 and taking away another 2 leaves 8
There are multiple ways of subtraction. However, working with 5 and 10 as the “stopping point” allows for easier calculation and should form the basis for all methods.