Cogito
Grade 1 Math · Chapter 7 · Lesson 5
Which Is More?
Compare two numbers by looking at the tens first.
10 problems · about 11 minutes · 1.NBT.B.3
What this lesson teaches
The child compares two two-digit numbers by comparing tens first, then ones, and says which is greater in words.
- Compare the tens first.
- More tens means the greater number.
- If the tens tie, compare the ones.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
4 problemsReview — Many Ways to Show a Number: 2 tens and 16 ones is which number?
Answer 36
Why 20 and 16 is 36.
Review — 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.
Warm Up
Straightforward practice. Get the method working first.
3 problemsWhich is greater, 30 or 27?
Answer 30
Why 30 has 3 tens. 27 has 2 tens.
What do you look at first?
Answer The tens.
Why Tens first, then ones if they tie.
Which is greater, 32 or 29?
Answer 32
Why 3 tens or 2 tens?
Build It Up
The same ideas with more to keep track of.
1 problemWhich is greater, 26 or 23?
Answer 26
Why The tens tie. Look at the ones.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsWhich is greater, 18 or 21?
Answer 21
Why Count the tens first.
Marbles: Leo has 24 marbles. Ana has 19. Who has more?
Answer Leo.
Why 24 has 2 tens. 19 has 1 ten.