Max Rescues the Time Machine: Addition and Subtraction Sprint

About this Grade 3 Mixed Add Subtract Drill

By third grade, students need to move beyond single-operation problems and tackle situations where addition and subtraction appear together. This mixed-add-subtract practice builds flexible thinking—the ability to read a problem carefully, decide which operation comes first, and execute multiple steps in the correct order. Real life is full of these situations: a child has 15 baseball cards, trades 3 away, then receives 8 more. How many does she have now? These aren't one-step problems; they require students to track changes over time, much like a time-machine journey through different numerical moments. Mastering mixed operations strengthens number sense, reduces careless errors, and prepares students for multi-step word problems in fourth grade and beyond. This skill also builds confidence—students who can handle "add then subtract" realize math is about logic, not just memorization.

What your student will practice

• Solve two-step problems combining addition and subtraction in any order
• Identify which operation to perform first based on problem wording
• Verify answers by checking work with inverse operations
• Apply left-to-right sequencing to compute mixed expressions accurately

Common mistakes to watch for

The most common error is ignoring order and randomly choosing which operation to do first. For example, in "Start with 12, add 5, then subtract 3," a student might subtract 3 first, getting 9, then add 5 to reach 14—when the correct path is 12 + 5 − 3 = 14. Watch for students who skip reading the problem and instead just scan for numbers. Another frequent pattern: students correctly add or subtract the first pair but forget to apply the second operation entirely, writing only a partial answer.