Year 1 Handbook
Addition within 20
See addition as joining parts and learn how making 10 can help.
What you are learning
See addition as joining parts and learn how making 10 can help.
Key idea
Addition combines parts to make a whole. We can rearrange the parts to make a helpful ten.
8+210+3=13
Worked example
8 + 5
8 + 5 = 13
- Start with 8.
- Make 10 by adding 2 from the 5.
- There are 3 left to add.
- 10 + 3 = 13.
Therefore, 8 + 5 = 13.
Another way
Count forwards
Start at 8 and count five more steps: 9, 10, 11, 12, 13.
Why this works
Breaking 5 into 2 and 3 does not change its total. It changes the order so one part makes a full ten first.
Common mistake
Remember
When adding, look for a part that helps you make 10.
Vocabulary
- add
- Put parts together.
- sum
- The answer to an addition.
- part
- One amount that is joined to another amount.
- whole
- The total after parts are joined.
Try one
Have a go before revealing the answer. These are optional learning checks: they are not scored and do not change your practice record.
Complete: 9 + 4 = ?
Which part of 6 can join 7 to make 10?