Fact Families

See how 3 + 5, 5 + 3, 8 − 3, and 8 − 5 belong together.

Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.

What children learn in Level 21

3, 5, and 8 are a family of numbers. 3 and 5 make 8.
They make four facts: 3 plus 5 is 8. 5 plus 3 is 8. 8 minus 3 is 5. 8 minus 5 is 3.
Adding puts the parts together. Subtracting takes a part away from the whole. They undo each other!
So if you know 4 plus 6 is 10, you also know 10 minus 6 is 4!
Use an addition fact you know to solve a subtraction problem.

Georgia's K-12 Mathematics Standards:

1.NR.2.3 — Recognize the inverse relationship between subtraction and addition within 20 and use this inverse relationship to solve authentic problems.