Mental math worksheets

In 3rd grade, mental math stretches to three-digit numbers with the same strategies: make a hundred, add a friendly number and compensate, subtract in easy chunks. The sheets stay horizontal because the goal is flexible thinking, not the written algorithm.

By grade

What students need to know

Turn hard numbers into friendly ones: to add 29, add 30 and then take 1 back.

This skill runs from 2nd grade through 3rd grade. Pick a grade above for level-matched sentences, teaching notes, and worksheets.

Mental math across the grades

2nd grade

Mental math worksheets for 2nd grade practice adding and subtracting two-digit numbers in your head with friendly-number strategies: add 30 instead of 29, then adjust. The problems sit horizontally on purpose: there's no column setup, just thinking.

3rd grade

In 3rd grade, mental math stretches to three-digit numbers with the same strategies: make a hundred, add a friendly number and compensate, subtract in easy chunks. The sheets stay horizontal because the goal is flexible thinking, not the written algorithm.

All addition & subtraction worksheets →

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