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This Mixed Add Subtract drill has 40 problems for Grade 1. Time Machine theme. Answer key included.
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Max's time machine landed in dinosaur country! He must solve math problems fast before the volcano erupts!
Standard: CCSS.MATH.1.OA.C.6
Preview
Page 1 — Drill
Page 2 — Answer Key
What's Included
About this Grade 1 Mixed Add Subtract Drill
Mixed addition and subtraction problems are crucial for first graders because they require flexible thinking—the ability to switch between adding and subtracting within the same set of problems. At ages 6-7, children are developing working memory and attention control, and practicing both operations together strengthens these skills. Unlike worksheets with only addition or only subtraction, mixed problems prevent students from relying on a single strategy or pattern. This mirrors real life: a child might earn 3 stickers, lose 1, then earn 2 more. By solving mixed problems, students learn to read each problem carefully, decide which operation to use, and build confidence with both addition and subtraction facts to 10 or 20. This foundation is essential for all future math, including word problems and multi-step thinking.
What your student will practice
- Identify whether a problem requires addition or subtraction based on key words
- Solve addition and subtraction problems fluently within 10 or 20
- Apply correct operation symbols and show work clearly
- Build automaticity switching between operations without confusion
Common mistakes to watch for
The most common error is students defaulting to one operation—often addition—regardless of the problem. For example, a child might automatically add 5 + 3 when they see '5 ___ 3,' even if the symbol is minus. Watch for students who pause before reading the operation sign or who solve the same operation repeatedly across different problems. Another frequent mistake is confusing the direction: writing 5 – 3 = 2 but calculating 3 – 5. You'll spot this when their work doesn't match their answer. Encourage students to touch or point to the operation sign before solving.
Create a simple real-world scenario using objects your child handles daily—toy cars, blocks, or crackers. Say: 'You have 6 cars. You give away 2. How many left?' Then immediately follow with: 'Now you find 3 more cars. How many do you have now?' This back-and-forth mirrors a time machine of events and naturally shows why knowing both operations matters. Repeat this playful pattern over a few days, and soon your child will automatically pause and check which operation to use rather than guessing.