Cogito
Kindergarten Math · Chapter 4 · Lesson 2
Breaking a Number Apart
Five can be four and one, or three and two.
10 problems · about 9 minutes · K.OA.A.3
What this lesson teaches
The child decomposes numbers up to 10 into pairs in more than one way.
- A number can be split into two parts many ways.
- The whole stays the same.
- Knowing the pairs makes adding easy.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Taking Away: 8 − 3 = ?
Answer 5
Why Five.
Review — Adding in Any Order: 2 + 6 = ?
Answer 8
Why Eight.
Review — Counting On: 6 + 2 = ?
Answer 8
Why Eight.
Review — Putting Two Groups Together: 3 + 4 = ?
Answer 7
Why Seven.
Warm Up
Straightforward practice. Get the method working first.
3 problems8 is 5 and how many?
Answer 3
Why Three.
5 is 4 and how many?
Answer 1
Why One more makes five.
6 is 2 and how many?
Answer 4
Why Count up to six.
Build It Up
The same ideas with more to keep track of.
2 problems7 is 3 and how many?
Answer 4
Why Count up to seven.
4 is 4 and how many?
Answer 0
Why None left.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
1 problemFive Sweets: Five sweets in two hands. Three in one hand. How many in the other?
Answer 2
Why Two.