In year 2 we have been learning to use “Think addition for subtraction” because it will help us become more efficient when calculating. Firstly we looked at missing parts in a part part whole model. We wrote the subtraction equation and addition number sentences. This helped us recognise that we can use addition to help us with subtraction.
After this we used part part whole models to complete addition and subtraction number sentences. We used the stem sentence, “The inverse of addition is subtraction.”
Finally, we put this into practice by using a beadstring to count on to the next benchmark. We then used addition to work out subtraction sentences such as 17-9. For example: I know that 1 more than 9 is 10 and 7 more than 10 equals 17. I know that 1 add 7 equals 8. Therefore the difference is 8. So, I now know that 17-9 is equal to 8.
How you can support at home:
- Practice making a number line at home and placing benchmarks up to 20.
- Use the benchmarks to help you count on.
- Use bar models to write addition and subtraction number sentences.