Comparing Three-Digit Numbers — Answer Key
Part A: Sort the Words
Sort each word or number into the correct category box.
1. Sort each pair by which number is greater: the first or the second.
First is greater
523 vs 498600 vs 599 Second is greater
312 vs 321645 vs 654789 vs 798431 vs 438 When comparing three-digit numbers, compare hundreds first, then tens, then ones. The larger digit in the leftmost place where they differ wins.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. 523 is greater than 498, so the first number is greater.
523 has 5 hundreds while 498 has 4 hundreds, so 523 > 498 and the first number wins.
2. In 312 vs 321, the second number is greater.
Hundreds match at 3, but tens are 1 vs 2, so 321 > 312 and the second number is greater.
3. In 645 vs 654, the second is greater because its tens digit is larger.
Hundreds tie at 6, but 5 tens is larger than 4 tens, so 654 > 645.
4. 600 vs 599: the first is greater because 6 hundreds beats 5 hundreds.
600 has 6 hundreds and 599 has 5 hundreds, so 600 > 599 based on the hundreds place.
5. If the hundreds match, we compare the tens next.
When hundreds are equal, the tens digit decides the comparison before moving to ones.
Part C: True or False?
Read each statement. Circle True or False.
1. In 431 vs 438, the second number is greater.
True False
Hundreds match at 4 and tens match at 3, but 8 ones beats 1 one, so 438 > 431.
2. 789 is greater than 798.
True False
Hundreds tie at 7, but 798 has 9 tens versus 8 tens, so 798 > 789, not the other way.
3. Compare hundreds first when looking at three-digit numbers.
True False
The hundreds place holds the biggest value, so we always compare it first when ranking three-digit numbers.
4. If hundreds are equal, the numbers must be equal.
True False
Even with equal hundreds, different tens or ones make the numbers unequal, like 312 and 321.