Description

Stop the slithering suspect with this Addition Review Math Mystery 4th Grade activity! ‘The Case of the Angry Adder’ is a high-engagement math review designed to practice advanced addition strategies like balancing equations and input/output tables alongside standard algorithms.

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).
• Easel by TPT: Complete the worksheets digitally for seamless online learning.

Addition Review Math Mystery 4th Grade Activity

To identify the Angry Adder, students must unlock five clues by correctly solving a variety of addition challenges:

• Clue 1: Mental Math (Horizontal Addition with 2-digit and 3-digit numbers)
• Clue 2: Pre-Algebra (Balancing Addition Equations with 2 and 3-digit numbers)
• Clue 3: Patterns (Addition Input/Output Tables with 3 and 4-digit numbers)
• Clue 4: Algorithms (Vertical Addition with 4-digit numbers)
• Clue 5: Large Numbers (Addition Algorithms with 4, 5, and 6-digit numbers)

Flexible for Any 4th Grade Classroom

Use this versatile addition worksheets alternative for:

• A fun review of the Addition unit
• 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 4th Grade Math Review

Q: What are “Input/Output Tables”?
A: Clue 3 focuses on Standard 4.OA.C.5 (Generate and analyze patterns). Students must determine the rule of the table (e.g., “Add 150”) to find the missing output. This is excellent practice for algebraic thinking.

Q: Why “Horizontal” Addition?
A: Clue 1 presents problems horizontally to encourage mental math strategies or to force students to practice rewriting problems vertically to align place values, which reduces calculation errors.

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 2-6 grade packs. We even have a blog post explaining how: learn how to differentiate here.

Other Grade Editions Available!

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

• 1st Grade Edition 
• 2nd Grade Edition
• 3rd Grade Edition
• 5th Grade Edition

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A complete answer key and printable awards are included!