Cogito
Grade 1 Math · Chapter 3 · Lesson 9
Adding and Subtracting to Ten
Mix them up and pick your own way.
10 problems · about 13 minutes · 1.OA.C.6, 1.OA.B.4
What this lesson teaches
The child solves mixed addition and subtraction facts within 10 and chooses an appropriate strategy.
- Adding and taking away go together.
- Read the sentence before you start.
- Pick the way that suits the numbers.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
1 problemReview — Subtracting From Ten: 10 − 6 = ?
Answer 4
Why 10 − 6 = 4.
Warm Up
Straightforward practice. Get the method working first.
5 problems7 − 2 = ?
Answer 5
Why 7 − 2 = 5.
6 + 4 = ?
Answer 10
Why 6 + 4 = 10.
8 − 8 = ?
Answer 0
Why 8 − 8 = 0.
9 − 5 = ?
Answer 4
Why Count up from 5 to 9.
3 + 6 = ?
Answer 9
Why Start with the bigger number.
Build It Up
The same ideas with more to keep track of.
2 problems10 − 3 = ?
Answer 7
Why 3 and 7 are partners to ten.
5 + 5 = ?
Answer 10
Why A double.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Bus: There are 8 people on a bus. 3 get off. How many are still on?
Answer 5 people
Why 8 − 3 = 5.
The Library: Mia has 4 books and borrows 3 more. How many books now?
Answer 7 books
Why 4 + 3 = 7.