Cogito
Grade 2 Math · Chapter 3 · Lesson 7
Comparing Three-Digit Numbers
Hundreds first, then tens, then ones.
10 problems · about 12 minutes · 2.NBT.A.4
What this lesson teaches
The child compares two three-digit numbers by comparing hundreds, then tens, then ones.
- Compare the hundreds first.
- Only look at the tens if the hundreds tie.
- Only look at the ones if the tens tie too.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — What Zero Means: 7 hundreds, 0 tens and 2 ones is which number?
Answer 702
Why It is 702.
Review — Three Ways to Write a Number: 400 + 70 + 5 in digits?
Answer 475
Why 400 + 70 + 5 = 475.
Review — Counting to 1,000: What comes after 499?
Answer 500
Why After 499 comes 500.
Warm Up
Straightforward practice. Get the method working first.
3 problemsWhich is greater, 548 or 584?
Answer 584
Why 8 tens beats 4 tens.
What do you compare first?
Answer The hundreds.
Why A hundred is worth more than any number of tens or ones.
Which is greater, 623 or 632?
Answer 632
Why Hundreds tie. Compare tens.
Build It Up
The same ideas with more to keep track of.
1 problemWhich is greater, 405 or 398?
Answer 405
Why 4 hundreds beats 3 hundreds.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problemsWhich is greater, 771 or 717?
Answer 771
Why Compare the tens.
Two Schools: One school has 428 pupils and another has 482. Which has more?
Answer 482
Why 8 tens beats 2 tens, so 482 is greater.
Collections: Leo has 199 cards and Ana has 201. Who has more?
Answer Ana.
Why 201 has 2 hundreds; 199 has only 1.