Cogito
Grade 1 Math · Chapter 3 · Lesson 6
Fact Families
Three numbers make four sentences.
10 problems · about 12 minutes · 1.OA.B.4, 1.OA.C.6
What this lesson teaches
The child generates all four equations from one number bond and uses one known fact to get another.
- Three numbers make a family of facts.
- Adding and subtracting are the same relationship.
- A double makes only two sentences, not four.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
7 problemsReview — What Changed?: 9 − ? = 6
Answer 3
Why 9 − 3 = 6.
Review — The Hidden Part: Whole 9, one part 4. What is the other part?
Answer 5
Why 4 + 5 = 9.
Review — Taking Away: 7 − 3 = ?
Answer 4
Why 7 − 3 = 4.
Review — Counting Up To Subtract: 9 − 7 = ?
Answer 2
Why Two hops, so the answer is 2.
Review — How Many More To Make It?: 3 + ? = 7
Answer 4
Why 3 + 4 = 7.
Review — Facts to Ten: 7 + 3 = ?
Answer 10
Why 7 + 3 = 10.
Review — Doubles and One More: 3 + 4 = ?
Answer 7
Why 3 + 3 = 6, and one more is 7.
Warm Up
Straightforward practice. Get the method working first.
2 problemsYou know 4 + 5 = 9. What is 9 − 4?
Answer 5
Why Same fact, read the other way.
How many different sentences does 4 and 4 make?
Answer Two.
Why A double makes only two, because both parts are the same.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
1 problemUsing What You Know: You know 6 + 3 = 9. What is 9 − 6?
Answer 3
Why They are the same fact read the other way.