Cogito
Grade 1 Math · Chapter 2 · Lesson 7
Doubles
Two groups the same size.
10 problems · about 10 minutes · 1.OA.C.6
What this lesson teaches
The child recognises and recalls doubles facts within 10.
- A double is two groups the same size.
- Doubles look balanced.
- Doubles are worth knowing by heart.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Finding the Missing Part: 5 + ? = 9
Answer 4
Why 5 + 4 = 9.
Review — What Does Equals Mean?: What does the equals sign mean?
Answer Both sides are the same amount.
Why Equals means the same amount as. That is why 9 = 6 + 3 works too.
Review — Adding in Any Order: 3 + 5 = 8. So what is 5 + 3?
Answer 8
Why Swapping the parts never changes the whole.
Review — Counting On With Pictures: Start at 9. Count on 1. Where do you land?
Answer 10
Why 9 + 1 = 10.
Warm Up
Straightforward practice. Get the method working first.
3 problems4 + 4 = ?
Answer 8
Why 4 + 4 = 8.
1 + 1 = ?
Answer 2
Why 1 + 1 = 2.
2 + 2 = ?
Answer 4
Why Two and two.
Build It Up
The same ideas with more to keep track of.
1 problem3 + 3 = ?
Answer 6
Why Three and three.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problems5 + 5 = ?
Answer 10
Why Two full fives.
Two Hands: Ben holds up 4 fingers on each hand. How many fingers is that?
Answer 8 fingers
Why 4 + 4 = 8.