Cogito
Grade 1 Math · Chapter 5 · Lesson 6
Taking From Ten
Break the teen number apart and take from the ten.
10 problems · about 14 minutes · 1.OA.C.6, 1.OA.B.4
What this lesson teaches
The child subtracts from a teen number by taking from the ten first, as in 12 − 9 = (10 − 9) + 2.
- Split the teen number into 10 and some ones.
- Take away from the ten.
- Then add the ones back on.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Counting On or Making Ten?: 8 + 2 = ?
Answer 10
Why 8 + 2 = 10.
Review — Start With the Bigger One: 6 + 9 = ?
Answer 15
Why 9 + 6 = 10 + 5 = 15.
Review — Making Ten From Eight: 8 + 5 = ?
Answer 13
Why 8 + 5 = 10 + 3 = 13.
Review — Making Ten From Nine: 9 + 5 = ?
Answer 14
Why 9 + 5 = 10 + 4 = 14.
Warm Up
Straightforward practice. Get the method working first.
3 problems13 − 9 = ?
Answer 4
Why 13 − 9 = 1 + 3 = 4.
16 − 8 = ?
Answer 8
Why 16 − 8 = 2 + 6 = 8.
12 − 9 = ?
Answer 3
Why 10 − 9 = 1, then add the 2.
Build It Up
The same ideas with more to keep track of.
1 problem15 − 8 = ?
Answer 7
Why 10 − 8 = 2, then add the 5.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problems11 − 7 = ?
Answer 4
Why 10 − 7 = 3, then add the 1.
Cupcakes: There were 14 cupcakes. 9 were eaten. How many are left?
Answer 5 cupcakes
Why 10 − 9 = 1, and 1 + 4 = 5.