Description

Celebrate 100 days of learning with this 100th Day of School Math 3rd Grade Activity! ‘The Case of the 100 Missing Treats’ is a high-engagement activity that makes practicing rounding and multiplication far more exciting than counting 100 items.

It’s the perfect no-prep math activity! This resource is loaded with options, including an optional video hook and a NEW ending video (with voiceovers!) to wrap up the case!

Easy Prep for Print

This resource is designed to be low-prep for you and high-engagement for your students.

• Printable PDF Version: Just print the worksheets, staple, and go.
• Digital Option: A Google Slides link is provided if you prefer to go paperless.

100th Day of School Math Mystery 3rd Grade Activity

To find the missing treats, students must unlock five clues by correctly solving a complete math review:

• Clue 1: Make 100 (Missing Addend Equations)
• Clue 2: Make 100 (Missing Subtrahend Equations)
• Clue 3: Rounding to the Nearest 10 or 100
• Clue 4: Multiplication Facts Mix (Facts range from 2-12)
• Clue 5: Number Patterns (Find the missing number / Determine the rule)

Flexible for Any 3rd Grade Classroom

Use this versatile 100th Day math worksheets alternative for:

• A fun celebration day activity
• Math centers or stations
• Homework or enrichment
• Your “early finisher” tub
• A lifesaver for your sub-tub!

Pacing & Timing

This is a comprehensive review that can take anywhere from 30 minutes to 2+ hours, depending on your students’ skill level. We recommend pacing it by one clue at a time.

Common Questions for this 3rd Grade Math Review

Q: Is this activity too “young” for 3rd graders?
A: Not at all! While the theme is the 100th Day, the math is strictly 3rd-grade level. Students will practice rounding, multiplication facts up to 12, and complex number patterns.

Q: Is this better than a normal worksheet?
A: Absolutely. Standard 100th day worksheets can be repetitive. This activity adds a narrative, a suspect list, and video hooks to keep students motivated to solve every problem.

Q: How does differentiation work with these?
A: That’s our secret weapon! Many of our stories are available for other grades, so you can “clue swap” with the 1-6 grade packs. We even have a blog post explaining how: learn how to differentiate here.

Other Grade Editions Available!

Love this ‘100 Missing Treats’ theme? This mystery is also available for other grade levels (great for differentiation)!

• 1st Grade Edition
• 2nd Grade Edition
• 4th Grade Edition
• 5th Grade Edition
• 6th Grade Edition

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A complete answer key and printable awards are included!