Cogito
Grade 1 Math · Chapter 10 · Lesson 1
How Many More? How Many Fewer?
Match two groups up and see what is left over.
10 problems · about 12 minutes · 1.OA.A.1
What this lesson teaches
The child solves compare-with-difference-unknown problems by matching the two quantities one to one.
- Comparing means looking at two groups.
- Match them one to one.
- The ones with no partner are the difference.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Telling Time to the Half Hour: How many minutes is half an hour?
Answer 30
Why Half an hour is 30 minutes.
Review — Telling Time to the Hour: Short hand on 4, long hand up. What hour?
Answer 4
Why It is 4 o’clock.
Review — Fourths and Quarters: How many fourths make one whole?
Answer 4
Why 4 fourths make the whole.
Review — Halves: How many equal shares are in a half?
Answer 2
Why A half is one of 2 equal shares.
Warm Up
Straightforward practice. Get the method working first.
3 problems10 birds and 6 cats. How many more birds?
Answer 4
Why 10 − 6 = 4.
In a compare problem, is anything added or taken away?
Answer No. The groups just sit there.
Why Nothing changes. You are only comparing.
7 red and 3 blue. How many more red?
Answer 4
Why 7 take away 3.
Build It Up
The same ideas with more to keep track of.
1 problem6 cats and 9 dogs. How many fewer cats?
Answer 3
Why 9 take away 6.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problems5 apples and 5 pears. How many more apples?
Answer 0
Why Every one has a partner.
In the Playground: 9 children on the swings and 4 on the slide. How many more?
Answer 5 more
Why 9 − 4 = 5, so 5 more are on the swings.