Unit Plan 4 (Grade 4 Math): Add/Subtract Multi-Digit—Fluency & Strategy

Focus: Use the standard algorithm and representations to add and subtract multi-digit numbers; apply reasonableness checks.

Grade Level: 4

Subject Area: Mathematics (Number & Operations in Base Ten)

Total Unit Duration: 5 sessions (one week), 45–60 minutes per session

I. Introduction

This week strengthens fluency with multi-digit addition and subtraction through visual models, the standard algorithm, and reasonableness checks. Students connect place-value reasoning to each step of the algorithm, explain regrouping precisely, and use estimation to verify the accuracy of their results.

Essential Questions

• How does the place-value system guide each step in multi-digit addition and subtraction?
• Why is it important to use reasonableness checks and estimation after computing?
• How can we explain regrouping clearly using representations and place-value language?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Add and subtract multi-digit whole numbers fluently using the standard algorithm.
2. Use place-value models (base-ten blocks, drawings, expanded notation) to represent addition and subtraction.
3. Justify regrouping steps with place-value reasoning and connect models to written procedures.
4. Apply estimation and rounding strategies to check the reasonableness of answers.
5. Communicate strategies clearly with correct units, labels, and mathematical vocabulary.

Standards Alignment — CCSS Grade 4 (spiral across the unit)

• 4.NBT.4: Fluently add and subtract multi-digit whole numbers using the standard algorithm.
• Mathematical Practices (MP.1–MP.8) threaded throughout.

Success Criteria — Student Language

• I can add and subtract multi-digit numbers using the standard algorithm accurately.
• I can use models and place-value reasoning to explain each regrouping step.
• I can use estimation to check if my answer is reasonable and explain why.