Skip to content

Welcome guest

Please login or register
Skip to product information

Kiwiland Education

Missing Numbers to 120 | Back to School Math Mystery | Grades 1–2 | Detective Mystery

$4.00 USD

Filling in the missing numbers to 120 turns detective when the teacher's lunchbox vanishes, a whole teacher goes missing, and the classroom art supplies disappear. In this no-prep, printable back-to-school Math Mystery, students work as private detectives who find the missing numbers to 120 (1 more, 1 less, before and after), match each answer to a suspect, and eliminate names until the culprit is caught. The self-checking, story-driven format builds real number-sequence and place-value fluency while easing 1st and 2nd graders into the school year — perfect for the first weeks back, math centers, morning work, homework, early finishers, substitute/relief days, indoor recess, and spiral review.

Quick Details

  • Skill: Missing numbers to 120 — 1 more, 1 less, before and after
  • Grades: 1–2 (1st, 2nd)
  • Format: 3 no-prep printable mystery worksheets in full color and black & white + suspect lists + full answer keys (PDF)
  • Theme: Back-to-School Math Detective Mystery

The 3 Mysteries

Each case pairs a number-chart worksheet with a suspect line-up: students fill in the missing numbers, match answers to clues, and cross off suspects until one is left:

  • Case One: The Teacher's Lunchbox — The teacher's lunchbox has gone missing. Fill in the missing numbers to work out which suspect took it.
  • Case Two: The Missing Teacher — A teacher has gone missing from school. Solve the number puzzles to eliminate suspects and track them down.
  • Case Three: The Missing Art Supplies — The classroom's art supplies have disappeared. Find the missing numbers to reveal who took them.

Why Teachers Love It

  • Zero prep — just print and hand out; a print-friendly black & white version is included too.
  • Self-checking — the suspect-elimination format means students catch their own mistakes and stay accountable.
  • Engagement that lasts — the detective story pulls in even reluctant and struggling students.
  • Differentiation-friendly — assign one case at a time or the full set; ideal for mixed-ability classrooms.

Skills Covered

  • Finding missing numbers to 120 (number sequences)
  • 1 more, 1 less, before and after
  • Place value and counting fluency
  • Logical reasoning and deductive process of elimination

What's Included

  • 3 print-and-go mystery worksheets (one per case), in full color and black & white
  • Matching suspect line-up lists
  • Full answer keys for every case
  • Student detective instructions

Best Used For

Back-to-school and first-weeks activities, math centers, independent practice, morning work, homework, early finishers, substitute/relief days, indoor recess, and spiral review — any time you want missing numbers to 120 practice that feels like a game.

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.

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.



Missing numbers to 120 back-to-school Math Mystery worksheets, detective cover grades 1-2

Missing Numbers to 120 | Back to School Math Mystery | Grades 1–2 | Detective Mystery

$4.00

Your Cart

Your Wishlist