3rd Grade Comparing Sums and Differences Worksheet: Which Side Is Bigger?

In 11 − 7 and 4 + 7, the 11 looks bigger than the 4. Yet 4 + 7 wins. This 3rd grade comparing sums and differences worksheet teaches children to work out both sides before they choose a sign. A worked example opens the page: 8 + 17 makes 25, 29 − 4 also makes 25, so the sign is =. Then come fourteen statements, from 3 + 5 and 10 up to 72 + 48 and 120. For each one, your child solves the left side and the right side, then writes <, > or = in the box. A second page gives the answer key.

Two sides, one sign

Each statement works like a balance. The sign tells which side is heavier, or that both weigh the same.

That is also the real meaning of the equal sign. It does not mean "the answer comes next." It means both sides have the same value, as in 58 + 12 and 37 + 33.

This idea matters a lot later, when third graders meet missing numbers in equations.

At the table: write the result under each side

Ask your child to write the result under each side, in small digits, before choosing the sign. For 13 + 6 and 8 + 9, that gives 19 and 17.

A small slip sits in the example. It says "right hand side" twice, but 8 + 17 is on the left. Point it out, as it is a good test of attention.

Some pairs can be solved without computing. In 18 − 7 and 18 − 9, taking away less leaves more, so the left side is bigger. In 17 − 0 and 16 − 0, nothing is taken away at all.

Finally, check all fourteen together with the answer key.

Two baskets at the store

This skill helps with money. Picture two baskets: one holds a $12 book and a $5 pen, the other a $20 game minus a $4 coupon. Which basket costs more?

Invent a few of these at home, with real prices. Let your child explain the answer out loud.

Once the page is done, name the effort: "You worked out both sides every time, before you chose the sign."