Cogito
Grade 1 Math · Chapter 3 · Lesson 3
Taking Away
Some go away, and you count what is left.
10 problems · about 11 minutes · 1.OA.A.1, 1.OA.C.6
What this lesson teaches
The child solves take-from-with-result-unknown stories and records them with the minus symbol.
- Taking away is subtracting.
- The minus sign means some go away.
- Count what is left, not what went.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
5 problemsReview — 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.
Review — Doubles: 4 + 4 = ?
Answer 8
Why 4 + 4 = 8.
Warm Up
Straightforward practice. Get the method working first.
3 problems7 − 3 = ?
Answer 4
Why 7 − 3 = 4.
5 − 1 = ?
Answer 4
Why 5 − 1 = 4.
6 − 2 = ?
Answer 4
Why Six, take two away.
Build It Up
The same ideas with more to keep track of.
1 problem10 − 3 = ?
Answer 7
Why Ten, take three away.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
1 problemBalloons: There are 9 balloons. 4 pop. How many are left?
Answer 5 balloons
Why 9 − 4 = 5.