Within 20: bridging ten and fact families
Fill the ten first, then put the rest. Add three numbers, swap the numbers round and find the four facts in a family.
📖 Start here: read the steps of the “Lesson” in order (1, 2, 3 …) and answer each question. Then continue with “Practice”.
- UK: Year 1
- France: grade 1
- Germany: grade 1
- Iran: grade 1
- Afghanistan: grade 2
- Syria: grade 1
- Palestine: grade 1
- Ukraine: grade 1
- Russia: grade 1
Guide
This studio is for Year 1. Your child works with apples and counters and answers by tapping a number. If they can't read yet, read the sentences to them.
The key strategy is bridging ten: for 8 + 5, 2 of the 5 fill the first frame (10), and 3 are left: 13. Subtraction goes back the same way: for 13 − 5, take 3 to get to 10, then 2 more.
When adding three numbers, first add the two that make 10. In addition you can swap the numbers round (commutative property). 9, 6 and 15 are a fact family: 9 + 6 = 15, 6 + 9 = 15, 15 − 9 = 6, 15 − 6 = 9.