Description

Celebrate 100 days with this 100th Day of School Math Mystery 2nd grade Activity! ‘The Case of the 100 Missing Treats’ is a high-engagement 100th Day of School activity for 2nd grade that turns a standard review into an exciting case-solving mission.

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 or Digital

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.
• Google Slides Digital Version: 100% paperless! Simply assign in Google Classroom. (Students must be in ‘edit mode’ to type).

100th Day of School Math Mystery 2nd grade Activity

To find the 100 missing treats, students must unlock five clues by correctly solving:

• Clue 1: Adding Multiples of 10 and 100
• Clue 2: Subtracting Multiples of 10 and 100
• Clue 3: Input/Output Tables – Add 100
• Clue 4: Input/Output Tables – Subtract 100
• Clue 5: Adding Numbers up to 100

Flexible for Any 2nd Grade Classroom

Use this versatile 100th Day of School activity for:

• A fun spiral review
• 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 giving students one clue at a time.

Common Questions for this 2nd Grade Math Review

Q: Is this just a **100th Day of School activity for 2nd grade**?
A: It’s designed for the 100th day, but it works as a powerful 2nd grade math review printable anytime you need to practice place value patterns!

Q: What skills does this mystery cover?
A: This is a comprehensive review. Students will practice adding and subtracting multiples of 10 and 100, working with input/output tables, and adding numbers to 100.

Other Grade Editions Available!

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

 

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A complete answer key is included!

 Frequently Asked Questions & Extras

• How long does a Math Mystery usually take to complete? Most of my mysteries are designed to take approximately 40–60 minutes. This can vary depending on whether students work individually or in pairs. Many teachers also love using them as a “Friday Fun” activity or breaking them up over two shorter sessions.
• Is there any prep involved? I know how busy you are, so I keep it “Print & Go.” There is no cutting, laminating, or complex setup required. Just print the clue pages and the opening story, and you are ready to start the investigation!
• What is a Math Mystery? How do I use them in the classroom or homeschool? <Check out this blog post to read more about how to use these teaching resources>
• How does differentiation work with these? That’s our secret weapon! Many of our stories are available for other grades, so you can “clue swap.” We even have a blog post explaining how: learn how to differentiate here.

• Add extra motivation: Download the Mystery Record & Rank Chart FREEBIE HERE
• Looking for more 2nd-grade resources? Math Mystery Worksheets & Activity Sheets for Teachers

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