When an addition crosses ten, make ten first. Start with the larger number, find how many more make ten, and split the other number into that amount and the rest. Then add the rest to ten. For a missing number, add the jump to ten and the jump from ten.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- bridge through ten
- make ten first, then add what is left
- split
- break a number into two parts
Worked examples
8 + 5
- 1.8 needs 2 more to make 10. Split 5 into 2 and 3.
- 2.8 + 2 = 10, then 10 + 3 = 13.
= 13
6 + 9
- 1.Start with the larger number, 9. It needs 1 more to make 10.
- 2.Split 6 into 1 and 5. 9 + 1 = 10, then 10 + 5 = 15.
= 15
8 + ? = 13
- 1.Count on from 8 to 10: that is 2. Then from 10 to 13: that is 3.
- 2.2 + 3 = 5, so 8 + 5 = 13.
= 5
For parents
Method: Bridge through ten
What to say: How many more does the bigger number need to make ten? What is left to add?
Common mistakes:
- Makes ten correctly, then gives only the ones left over and forgets the ten.
- Uses part of the second number to make ten, then adds all of it again.
- Counts on but says the starting number as the first step, so the answer is one out.
- Counts on one more than the number being added.
- For a missing number, finds only the jump up to ten.
- For a missing number, finds only the jump from ten to the total.