Unit Plan 6 (Grade 3 Math): Place Value to 1,000 & Rounding

Focus: Read/write numbers to 1,000, compare using place value, and round to the nearest 10 or 100 to make estimates in context.

Grade Level: 3

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

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

I. Introduction

Students deepen place-value understanding within 1,000 and use it to make sensible comparisons and estimates. They represent numbers in multiple forms and on number lines, identify benchmarks, and reason about the halfway point to round to the nearest 10 or 100. Estimation is applied to quick real-world decisions.

Essential Questions

• How does place value help me read, write, compare, and round numbers?
• What does “nearest 10” or “nearest 100” mean on a number line?
• When is an estimate better than an exact answer, and how do I check its reasonableness?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Read, write, and represent numbers to 1,000 in standard, expanded, and word forms.
2. Compare and order numbers using place-value reasoning and number lines.
3. Round whole numbers to the nearest 10 or 100 using benchmarks and the halfway idea.
4. Choose and justify estimates that make sense for real-world situations, attending to precision.
5. Communicate clearly with labels, forms, and models; check for reasonableness.

Standards Alignment — CCSS Grade 3

• 3.NBT.1: Use place value understanding to round whole numbers to the nearest 10 or 100.
• Mathematical Practices: MP.2 (Reason abstractly and quantitatively), MP.6 (Attend to precision).

Success Criteria — Student Language

• I can show a number to 1,000 in standard, expanded, and word form.
• I can explain which number is greater using hundreds–tens–ones or a number line.
• I can round to the nearest 10 or 100 and tell how I knew (benchmarks and halfway).
• I can choose an estimate and explain why it is reasonable for the situation.