Multiplying by Multiples of 10

Inside the case file

These multiplying by multiples of 10 worksheets give your 3rd grade class ten CSI Mini Mystery Detective math activities with a candy factory theme. It's 3.NBT.A.3 practice that starts with multiply by tens facts and moves on to multiplication word problems and two-step problems. Use the cases in math centers, as morning work or for homework while you teach multiplication. They're no prep, and you get an answer key with every case.

Half of the cases are drawn pages. Students count candy boxes, read prices off a prize counter, fill in a times grid, jump along number lines and finish order forms for a birthday cake. The other half are written problems. Every answer crosses one suspect off, and the one left at the end is the villain. Students check their own work as they go, and you have very little grading to do.

What's Inside

• 10 one-page cases with 20 problems on each, 200 problems in all
• An answer key for every case
• 5 drawn pages and 5 pages of written problems
• A reference page with examples: tens, using a fact you know, the times grid, how many more, two-step problems and number lines
• Contents, teacher instructions, a case log for students and a Head Candy Inspector certificate
• 30 pages. Everything prints in black and white

The Cases

1. The Chocolate Bar Caper - candy boxes with tens in each
2. The Popsicle Puzzle - prize counter ticket orders
3. The Cupcake Crumble - filling in a times grid
4. The Conveyor Belt Chaos - jumps of tens on number lines
5. The Cherry Topping Theft - how many more comparisons
6. The Empty Cone Con - two-step candy problems
7. The Birthday Cake Blunder - order forms with boxes and candies
8. The Sundae Switch - one-step multiplication word problems
9. The Chef Hat Heist - a mixed challenge
10. The Grand Opening Disaster - mixed review of every type

When to Use This Resource

The first four cases are pictures. Students see the tens as boxes of chocolate, ticket prices, grid columns and jumps on a number line before they work with the numbers on their own. Case 5 asks how many more, and Case 6 adds a second step. Cases 7 and 8 put the skill into order forms and word problems. The last two mix everything, including turnaround facts, repeated addition and parentheses, and they're a good fit for test prep. You can also give a single case to a small group, leave a few in your sub plans or use them for homeschool practice.

Grade Levels

Written for 3rd grade (3.NBT.A.3). 4th grade classes can use it as a warm-up before multiplying bigger numbers in 4.NBT.B.5.

Why Teachers Love Mystery Detectives

Every Mystery Detective pack works the same way. Once your class has solved one case, they know what to do with the next one, in this pack or any other. Each case also stands on its own, which means you can choose the one that fits what you're teaching that day. Naming the villain gives every page a clear end point, and the answer key lets you check a page quickly.

Want more cases like these?

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