Skip to content

Welcome guest

Please login or register
Skip to product information

Kiwiland Education

3-Digit Addition with Regrouping | Mystery Detective Worksheets | Grades 2–5 | Printable Detective Pack

$4.00 USD

3 digit addition with regrouping math activities for 2nd grade and 3rd grade: five math cases, each a Mystery Detective page of column sums. Print and go with full answer keys: no prep math worksheets for morning work, math centers, early finishers, homework and sub plans. Three digit addition with regrouping practice for 2nd grade and 3rd grade, set around school so it fits any week of the year. It runs as a math center, a homework set or a 3rd grade math review, and the CSI Mini Mystery Detective format means students check their own work.

Three digit carrying is where a class learns to write the columns out properly, and five cases with a missing hat make that the fun part. Every page is self-marking, and five math pages make one Mystery Detective download.

Students carry across the tens and hundreds to find each total, then use it to cross off one clue. Each page has four clue lists: who, where, when and what. The stories are about school life, like missing pens and a lost school hat. When students finish with one clue left in every list, they know their carrying was right.

 

The Cases

  1. The Missing Pens - pens gone from the classroom
  2. The Mystery Gift - a present with no name on it
  3. The Vacation - a student's surprise trip
  4. The Missing Hat - a lost school hat
  5. Student Prize - good deeds and a prize

 

What's Inside

  • Five color case pages of 3 digit addition with regrouping
  • The same five in black and white
  • An answer key for each case
  • Four clue lists on every page
  • Teacher instructions

 

What Is a CSI Mini Mystery Detective?

It's a printed case on a single page: a crime at the top, addition problems underneath and short clue lists beside them. Every clue has a number. Students cross off clues as their answers match, and the leftovers are the solution.

 

When to Use This Resource

Use it once 3 digit addition has been taught and students are ready to practice on their own. It's also good to have after a long break, when carrying needs a refresher. The cases suit math centers, small groups, sub days and homeschool.

 

Grade Levels

Written for 2nd grade and 3rd grade. 3rd graders can use it before 4 digit addition starts.

 

Why Teachers Love These Cases

  • Print and hand out
  • Color and black and white
  • School stories
  • Students can check their own totals

 

Want more cases like these?

Follow Kiwiland Education to discover more CSI Mini Mystery Detective cases, no-prep math activities, and detective-themed printables for elementary classrooms.

Follow Kiwiland Education on TPT ↗

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

  • After purchase, you’ll receive an email with a download link within minutes.
  • Make sure to check your spam or promotions folder if you don't see it right away.
  • If you experience any issues accessing your files, please contact us and we’ll help you promptly.

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

How Math Mysteries Work

Each Math Mystery resource gives you five one-page cases that turn math practice into a clue-based investigation. Here's exactly how a case plays out.

CASE FILE 5 MYSTERIES

Every set is a ready-to-solve investigation

Students become the math detective. They read a story, crunch the numbers, and use their answers as evidence to rule out suspects — until only the culprit is left standing.

1
STEP 01

Read the Case

Each mystery opens with a short, themed story that sets the scene and tells students exactly what they're trying to find out — who took something, what went missing, or what really happened.

Hooks them in seconds
2
STEP 02

Solve the Problems

Students work through a set of problems built around the target skill. Every answer is a clue — so there's a real reason to get each one right.

Focused skill practice
3
STEP 03

Eliminate Suspects

Students match their answers against the suspect list and cross off names one clue at a time. Wrong math means the wrong suspect — so the activity self-checks as they go.

Self-checking built in
4
STEP 04

Crack the Case

One suspect is left — and students reveal who did it. The payoff makes review feel like a win, and they're ready to start the next case.

The satisfying reveal

See it in action

SOLVE A CLUEAnswer = 576
→
MATCH THE ANSWER576 = Bianca
→
CROSS OFFBianca
No apps. No logins. No prep. Just print, hand out, and let them investigate.

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

Why Teachers Use Math Mysteries

Skill practice that feels like a case worth solving — and a download that quietly does a lot of your planning for you.

5one-page cases per set
0prep or setup time
color & black-and-white
answer keys included

Five Mysteries in One

Every download includes five separate one-page cases — enough for a full week of practice, a center rotation, or a sub-day backup that's always ready to go.

Truly No-Prep

No cutting, laminating, apps, or logins. Print in full color or black-and-white and hand them straight out — that's the whole setup.

Self-Checking by Design

Students need the right answers to rule out the right suspects, so accuracy matters — and the included answer keys mean no grading for you.

Fits Any Routine

Use one case as a morning warm-up, or spread the five across the week for centers, partner work, early finishers, or intervention.

Keeps Students Hooked

The mystery format gives even reluctant mathematicians a reason to keep solving. Review starts to feel like a game, not another worksheet.

Differentiation-Friendly

Great for on-level practice, an extension for advanced students, or a targeted review pass for anyone who needs another go at the skill.

NO PREP PRINT & GO ANSWER KEYS INCLUDED

What's in every Math Mystery set

5 full-color mysteries 5 black-and-white versions 5 complete answer keys Print-and-go teacher page Bonus coloring page
Practice that feels like a case worth cracking.

Frequently Asked Questions About Math Mysteries

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

Is this Math Mystery a digital activity?

No. This is a printable PDF resource. Students complete the 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 Math Mystery straight away.

How do students solve the Math Mystery?

Each resource includes five one-page cases. In each one, students solve the math problems and use their answers to eliminate suspects until only one remains and the case is cracked.

Can this Math Mystery be used for sub plans?

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

Can this Math Mystery be used for homeschool?

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



3-digit addition with regrouping worksheets 2nd 3rd grade

3-Digit Addition with Regrouping | Mystery Detective Worksheets | Grades 2–5 | Printable Detective Pack

$4.00

Your Cart

Your Wishlist