Cogito
Grade 1 Math · Chapter 7 · Lesson 4
Many Ways to Show a Number
The same number can be built in more than one way.
10 problems · about 12 minutes · 1.NBT.B.2
What this lesson teaches
The child represents one number in several ways, such as 34 as 3 tens 4 ones, 2 tens 14 ones, and 34 ones.
- One number can be shown in many ways.
- 34 is 3 tens 4 ones, or 2 tens 14 ones.
- Grouping changes. The amount does not.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Multiples of Ten: Three tens is which number?
Answer 30
Why Three tens is 30.
Review — Tens and Ones on a Mat: How many tens are in 31?
Answer 3
Why 31 is 3 tens and 1 one.
Review — Counting Beyond 20: What comes right after 20?
Answer 21
Why After 20 comes 21.
Review — Asking Questions About Data: 5 apples and 2 stars. How many in all?
Answer 7
Why 5 + 2 = 7.
Warm Up
Straightforward practice. Get the method working first.
3 problems2 tens and 16 ones is which number?
Answer 36
Why 20 and 16 is 36.
Does bundling change how many you have?
Answer No. Only the grouping changes.
Why The blocks were only rearranged.
1 ten and 17 ones is which number?
Answer 27
Why 10 and 17.
Build It Up
The same ideas with more to keep track of.
1 problem2 tens and 12 ones is which number?
Answer 32
Why 20 and 12.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problems25 has 1 ten. How many ones are left?
Answer 15
Why 25 take away 10.
Two Shelves: Ana has 2 tens and 14 ones. How many is that?
Answer 34 blocks
Why 20 and 14 is 34.