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Kiwiland Education

100th Day of School Missing Numbers to 100 Math Mystery Activity

$4.00 USD

Finding the number before and after to 100 becomes a 100th Day of School detective adventure in this no-prep Math Mystery, where your students hunt down the missing chocolates, the hidden gremlins, and the principal's secret age. Every printable, self-checking mystery works the same clever way: students fill in the missing number that comes before or after, match their answer to a clue, cross a suspect or location off the list, and solve the case. Perfect for Kindergarten, 1st, and 2nd grade 100th Day activities, math centers, morning work, homework, early finishers, substitute and relief days, indoor recess, and number-sense review.

Quick Details

  • Skill: number before and number after (to 100)
  • Grades: Kindergarten, 1st, 2nd
  • Format: 5 mysteries + full answer keys (printable PDF)
  • Theme: 100th Day of School

The 5 Mysteries

  • Missing Chocolates (number after) — A teacher bought chocolates for the 100th day but they have gone missing. Students find the number after to work out where they are.
  • Missing Number to 100 (number after) — A number has vanished and nobody knows which one. Students solve the clues to reveal the missing number.
  • Missing Stickers (number after) — A teacher's 100 stickers have disappeared. Students use the number after to track down where they are hidden.
  • 100 Hidden Gremlins (number before) — 100 gremlins are hiding somewhere in the school. Students find the number before to discover their location.
  • Principals Birthday (number before) — It is the principal's birthday and no one knows their age. Students work out the number before to reveal how old they are.

Why Teachers Love It

Zero prep — just print and hand out. The mysteries are completely self-checking, so students know they are on track without you marking every page. The detective hook pulls in reluctant and struggling learners, while the elimination structure makes differentiation and independent practice easy — a perfect fit for the 100th Day of School.

Skills Covered

Identifying the number before and the number after within 100, number sequencing and place value to 100, and logical reasoning through deductive clue elimination.

What is Included

  • 5 100th-Day-themed mystery worksheets
  • Full answer keys for every mystery
  • Student instruction page

Best Used For

No-prep printable number-before-and-after practice for the 100th Day of School, math centers, morning work, homework, early finishers, sub days, and number-sense review in Kindergarten, 1st, and 2nd grade.

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

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.



100th Day of School Math Mystery number before and after to 100 for Kindergarten, 1st and 2nd grade - no-prep printable

100th Day of School Missing Numbers to 100 Math Mystery Activity

$4.00

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