Make Ten to Add Past 10
Split the smaller number so one addend makes 10, then add what is left.
Use this when both numbers are single digits and the sum goes past 10. Adding across 10 in one jump is the slow part. Make a ten first. Adding onto 10 is just saying the other number with a one in front.
Look at 8 + 5. 8 is closer to 10, and it needs 2 more. Those 2 come out of the 5, so 5 splits into 2 and 3. The 2 finishes the ten. The 3 is still left to add.
8 + 2 + 3
Add the 2 to 8 first.
10 + 3 = 13
Then add the 3 that is left.
- See how many the closer number needs to make 10.
- Split that many off the other number.
- Add to make 10.
- Add the leftover to 10.
9 + 6 follows the same path. 9 needs 1, so 6 splits into 1 and 5. 9 + 1 = 10, then 10 + 5 = 15. 7 + 6: 7 needs 3, so 6 splits into 3 and 3, and 10 + 3 = 13.
Watch out
- Splitting off the wrong amount. 8 needs 2 from 5, not 3.
- Adding the leftover back onto 8. It joins the 10.
- Making a ten from the smaller number when the other one is closer.
Which number should become 10?
The one closer to 10. For 8 + 5, build the ten from 8. For 9 + 6, build it from 9.
How do you make a ten for 9 + 6?
Split 6 into 1 and 5. 9 + 1 = 10, then 10 + 5 = 15.
Math practice for Make Ten
Add within 20
Practice this