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"Great resource, low prep, easy to use, and fun! Thank you for sharing this! Highly recommend to other teachers!"

Brandie K.

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"My students loved this resource! They were engaged and were able to complete the tasks with ease."

Gina H.

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"I have enjoyed every purchase I've made from your store. The students are always so engaged!"

Karen C.

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Kiwiland Education

Addition & Subtraction CSI Mystery Worksheets | Grades 3–5 | AI Classroom Takeover

$4.50 USD

Looking for a fun and low-prep way to review addition and subtraction with regrouping? This AI-themed CSI Mystery Detective is the perfect back-to-school or summer review math activity for your 3rd grade, 4th grade, and 5th grade students. With a built-in detective storyline, students solve a series of puzzles to uncover who's behind the AI Classroom Takeover!

This printable mystery engages students in solving math problems and narrowing down suspects. As they complete each activity, they eliminate options from the list until only one person remains. It's a great way to reinforce fluency and critical thinking in a meaningful context.

What's Included:

  • Adding multiple 2-digit numbers
  • 3-digit addition with regrouping
  • Subtraction from 1000
  • 3-digit subtraction with regrouping
  • Answer sheets included
  • Print-and-go format (color and black-and-white)

CSI Mystery Detective packs are independent escape room or crack-the-code types of fun math activities where instead of using locks, students identify suspects using puzzles and word problems. They're perfect for back-to-school, summer school, or end-of-year math review.

This mystery is designed for 3rd and 4th grade students, but can also be used with struggling 5th graders who need extra practice or gifted 2nd grade students looking for a challenge. These make excellent sub plans or review tasks for early finishers—and are also a hit with homeschool families!

Love this resource? Follow Kiwiland Education to discover more addition and subtraction Mystery Detectives, printable CSI games, and engaging seasonal activities!

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Kiwiland Education

If you are interested in this product and your students enjoy Mystery Detectives, I have additional resources that will complement this one.

CSI: CSI Mystery Detective - Alien Invasion

CSI: CSI Mystery Detective - Zombie Attack

CSI: CSI Mystery Detective - Jungle Juice Fever

All of our products are digital downloads — no physical items will be shipped.

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Due to the nature of digital products, all sales are final.

We do not offer refunds or exchanges once a file has been downloaded.

However, if you encounter any problems with your download or the product itself, please reach out — we're happy to assist.

  • Thank you from Kiwiland Education

"Great resource, low prep, easy to use, and fun! Thank you for sharing this! Highly recommend to other teachers!"

Brandie K.

Verified buyer

"My students loved this resource! They were engaged and were able to complete the tasks with ease."

Gina H.

Verified buyer

"I have enjoyed every purchase I've made from your store. The students are always so engaged!"

Karen C.

Verified buyer

How CSI Math Mysteries Work

CSI Math Mysteries turn regular math practice into a clue-based investigation. Students solve problems, use their answers as evidence, and eliminate suspects until the case is solved.

1

Read the Case

Students begin with a short mystery scenario and find out what needs to be solved.

2

Solve the Clues

Each clue gives students focused math practice using the target skill for that resource.

3

Eliminate Suspects

Students use their answers to remove suspects from the investigation one clue at a time.

4

Crack the Case

By the end, only one suspect remains and students can reveal the answer to the mystery.

No apps, locks, passwords, or student logins are required. Just print and go.

New to the format? Read What Is a Math Mystery? for how they work and how to run one in class.

Why Teachers Use CSI Math Mysteries

CSI Math Mysteries turn skill practice into a clue-based investigation students want to solve. They are easy to prep, flexible for different classroom routines, and help students practice math skills while using logic, reasoning, and careful problem solving.

Teacher-Friendly Review

Practice that feels like a mystery, not another worksheet.

CSI Math Mysteries help students stay focused by turning skill practice into a clue-based case. They are easy to prep, simple to use, and flexible enough for busy classroom routines.

No-Prep and Print-and-Go

Use the pages right away for review, math centers, sub plans, small groups, early finishers, or homeschool math.

Encourages Careful Thinking

Students need accurate answers to eliminate suspects, which encourages checking, reasoning, and attention to detail.

Easy to Fit Into Lessons

Use a full mystery in one session or split the clues across centers, partner work, intervention, or review rotations.

Builds Student Confidence

The mystery format gives students a clear purpose for practicing math skills and helps make review feel more rewarding.

CSI Math Mysteries combine focused math practice with problem solving, logic, and a detective-style task that students can complete independently or with support.

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Frequently Asked Questions For CSI Math Mysteries

Printable CSI Math Mystery worksheets that turn math practice into clue-based detective investigations.

Is this CSI Math Mystery a digital activity?

No. This is a printable PDF resource. Students complete the CSI Math Mystery on paper. No physical item will be shipped.

Do students need apps, locks, passwords, or logins?

No. Students do not need apps, locks, passwords, or logins. Teachers can print the pages and use the CSI Math Mystery straight away.

How do students solve the CSI Math Mystery?

Students solve math clues and use their answers to eliminate suspects. Each correct answer helps them narrow down the case until only one suspect remains.

Can this CSI Math Mystery be used for sub plans?

Yes. CSI Math Mysteries work well for sub plans because students can work through the clues independently, with a partner, or in small groups.

Can this CSI Math Mystery be used for homeschool?

Yes. This printable CSI Math Mystery can be used for homeschool lessons, tutoring, review practice, enrichment, or extra math support.

Will this work for early finishers or math centers?

Yes. CSI Math Mysteries are a good fit for early finishers, math centers, small groups, independent work, review lessons, and extra practice activities.

3-digit addition and subtraction worksheets regrouping mystery detective printable

Addition & Subtraction CSI Mystery Worksheets | Grades 3–5 | AI Classroom Takeover

$4.50

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