Comparing and Ordering Three-Digit Quantities

Elementary Depth 8 in the knowledge graph I know this Set as goal
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comparison ordering place-value

Core Idea

When comparing three-digit numbers, look at the hundreds place first. If they're equal, look at the tens place; if still equal, look at the ones place. You can represent comparisons with symbols (<, >, =) or ordered lists (least to greatest).

How It's Best Learned

Use base-ten blocks to visually compare quantities. Practice comparing numbers without blocks, verifying answers with blocks. Order sets of numbers and explain the reasoning.

Common Misconceptions

Explainer

You already know how place value works: in a three-digit number like 352, the 3 stands for 3 hundreds (300), the 5 stands for 5 tens (50), and the 2 stands for 2 ones (2). Comparing two numbers is really asking: which one represents a bigger total? The smartest way to find out is to start with the most powerful digit — the hundreds place — because a single hundred is worth more than all nine tens and nine ones combined (100 > 99).

Here is the rule: look left first. Compare the hundreds digits of the two numbers. If one is larger, that number is greater — and you are done. You never even need to look at the tens or ones. For example, 472 vs. 318: 4 hundreds beats 3 hundreds, so 472 > 318, full stop. Only when the hundreds digits are *equal* do you need to move right and compare the tens digits. And only if the tens are also equal do you look at the ones.

The symbols <, >, and = are shorthand for this comparison. The symbol always "opens toward" the larger number — think of it as a hungry mouth eating the bigger meal. So 472 > 318 means "472 is greater than 318." You can flip it and write 318 < 472 — same relationship, different direction. When you need to order several numbers — say, from least to greatest — you apply this same left-to-right comparison repeatedly, like sorting a hand of cards by color first, then by value within each color. Start by sorting on hundreds, then break ties with tens, then with ones. The result is a line of numbers from smallest to largest, each one checked systematically against its neighbors.

Practice Questions 5 questions

Prerequisite Chain

Longest path: 9 steps · 11 total prerequisite topics

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