Cogito
Grade 1 Math · Chapter 7 · Lesson 1
Counting Beyond 20
Count to 40 and find the pattern that repeats.
10 problems · about 9 minutes · 1.NBT.A.1
What this lesson teaches
The child counts to 40 and notices that each decade repeats the same one-to-nine pattern.
- Counting keeps going past 20.
- Every row of the chart holds ten numbers.
- The endings 1 to 9 repeat in every row.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Asking Questions About Data: 5 apples and 2 stars. How many in all?
Answer 7
Why 5 + 2 = 7.
Review — Sorting and Showing Data: A graph shows 4 apples and 6 stars. How many in all?
Answer 10
Why 4 + 6 = 10.
Review — How Much Longer?: A 9-cube stick and a 4-cube stick. How much longer is the first?
Answer 5
Why 9 − 4 = 5.
Review — Why Same-Size Units?: Why must you say which unit you used?
Answer Because a number alone does not say how long.
Why 8 cubes and 8 blocks are different lengths, so the unit matters.
Warm Up
Straightforward practice. Get the method working first.
3 problemsWhat comes right after 20?
Answer 21
Why After 20 comes 21.
Which row does 33 sit in?
Answer The row that starts at 31.
Why 33 sits between 31 and 40.
What comes after 29?
Answer 30
Why That row is full at 30.
Build It Up
The same ideas with more to keep track of.
1 problemWhat comes after 34?
Answer 35
Why Count on one.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsWhat comes after 39?
Answer 40
Why The last row ends there.
Counting Stickers: Leo counts 27 stickers, then finds one more. How many now?
Answer 28 stickers
Why After 27 comes 28.