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Kiwiland Education

Mixed Numbers and Fractions | Mystery Detective Worksheets | Grades 3–6 | Detective

$4.00 USD

Mixed numbers and fractions worksheets for 4th grade and 5th grade: five math sheets, each a Mystery Detective page with the suspect lineup beside the questions. Print and go with full answer keys: no prep math centers, early finishers, homework, morning work and sub plans. A box of chocolates with no name, a birthday nobody will admit to and a new car with no owner carry the cases, each answer crosses a suspect off the lineup until one name is left, and a wrong fraction matches no suspect, so the marking is done by the CSI Mini Mystery Detective lineup before the pen comes out.

Fractions are the part of the week a class will put off, and a box of chocolates on the teacher's desk with no name on it is what gets them started. Every answer takes one suspect off the lineup, so students check their work on the way to the culprit, and one case fills a period. Five CSI Mini Mystery Detective math cases covers the last week of the fractions unit.

The Cases

  1. Box of Chocolates - a box on the desk, unsigned
  2. Birthday Party - somebody has a birthday today
  3. Monster Teacher - one of them is in disguise
  4. New Car - a new car and no owner named
  5. Acts of Kindness - good deeds and nobody owning up

What's Inside

  • Five case files on mixed numbers and fractions
  • A suspect lineup beside the questions, so one answer removes one name
  • A black and white copy of all five cases for everyday printing
  • A red-ink answer key for every case
  • Five separate stories, so no two pages read the same
  • Print and go: no cutting, no laminating, nothing to prepare

What Is a CSI Mini Mystery Detective?

A CSI Mini Mystery Detective is a printable case: one crime, one lineup, and the questions that rule the suspects out. Each suspect carries a value, the answers produce those values, and a match strikes that name off until one is left. The elimination only works when the fractions are right, which is what makes a mistake visible instead of hidden.

When to Use This Resource

Use this once mixed numbers have been taught and the class is working unaided, which is also the point where careless conversion creeps in. It comes out again before testing, because fraction questions are a standing source of dropped marks. Everything a student needs is printed on the page, so it slots into a centers rotation or a sub folder with nothing to explain.

Use it for math centers, early finishers, homework, test prep, morning work, sub plans and homeschool lessons, with a whole class, a small group or one student.

Grade Levels

Written for 4th grade and 5th grade. Fourth graders use these as the fractions unit closes, and fifth graders use them as a refresher before operations with mixed numbers.

Why Teachers Love These Cases

  • A wrong conversion matches no suspect, so students check themselves
  • Nothing to prepare beyond pressing print
  • Five cases makes a week of fraction practice from one file
  • Works with a whole class, a small group, partners or one student

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

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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.



Mixed numbers and fractions worksheets 4th 5th grade

Mixed Numbers and Fractions | Mystery Detective Worksheets | Grades 3–6 | Detective

$4.00

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