Max Discovers the Lost City: Addition Subtraction Quest!

About this Grade 3 Mixed Add Subtract Drill

By Grade 3, students encounter real-world math problems that don't fit neatly into "just adding" or "just subtracting." Mixed operations—where students solve problems containing both addition and subtraction—build flexible thinking and prepare them for multi-step reasoning. This skill matters because third graders are developing the mental stamina to hold onto intermediate answers while working through a sequence of operations. When your child tracks allowance money (earning, then spending, then earning again), manages game scores, or helps with simple shopping calculations, they're naturally encountering mixed operations. Practicing these drills strengthens working memory and number sense simultaneously, laying the foundation for order of operations they'll encounter in upper elementary grades. Students who master mixed-add-subtract become confident problem-solvers who don't panic when a math situation requires more than one step.

What your student will practice

• Solve two-step problems combining addition and subtraction within 100
• Maintain accuracy while tracking intermediate sums and differences
• Apply left-to-right calculation strategy with mixed operations
• Build automaticity with fact fluency while managing multiple operations

Common mistakes to watch for

Third graders frequently forget the intermediate result—they'll add two numbers correctly, then subtract from the wrong number in the next step. Another common pattern is reversing the operation mid-problem: they might subtract when the problem asks them to add next, especially when tired or rushing. Watch for students who ignore operation signs and simply compute left-to-right with one operation throughout. You can spot this by checking their written work—do the intermediate answers make sense? Ask them to say aloud what they're doing before they write their final answer.