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Grade 2 Math Units

Unit Plan 24 (Grade 2 Math): Place-Value Reasoning—Compare & Explain

Compare three-digit numbers using hundreds–tens–ones reasoning, expanded form, and models; justify with >, <, = and clear place-value arguments.

Dr. Michael Kester-Haynes

• 5 min read
Unit Plan 24 (Grade 2 Math): Place-Value Reasoning—Compare & Explain

Focus: Compare three-digit numbers and justify decisions using base-ten models, expanded form, place-value charts/language, and comparison symbols (>, <, =).

Grade Level: 2

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

Total Unit Duration: 5 sessions (one week), 35–45 minutes per session

I. Introduction

Students deepen understanding that hundreds, tens, and ones represent bundled units (10 tens = 1 hundred). They read/write numbers in standard, number name, and expanded form, then compare numbers using place-value reasoning and symbols. Learners explain and critique reasoning (MP.3) with precise language.

Essential Questions

  • How does the place of a digit change its value?
  • How can expanded form and models help me compare numbers?
  • What evidence makes a strong mathematical argument about which number is greater?

II. Objectives and Standards

Learning Objectives — Students will be able to:

  1. Describe any three-digit number as hundreds–tens–ones; explain bundling (10 tens = 1 hundred).
  2. Read and write numbers to 1,000 in base-ten numerals, number names, and expanded form.
  3. Compare two three-digit numbers using place-value reasoning and record results with >, <, =.
  4. Construct and share clear arguments and critiques using models and precise vocabulary (MP.3).

Standards Alignment — CCSS Grade 2

  • 2.NBT.1: Understand that the three digits of a three-digit number represent hundreds, tens, ones; 100 is a bundle of ten tens.
  • 2.NBT.3: Read and write numbers to 1,000 using base-ten numerals, number names, and expanded form.
  • 2.NBT.4: Compare two three-digit numbers based on meanings of the digits and record with >, =, <.
  • Mathematical Practices: MP.3 (Construct viable arguments & critique the reasoning of others).

Success Criteria — Student Language

  • I can tell how many hundreds, tens, and ones are in a number.
  • I can write a number in expanded form and number name.
  • I can compare two numbers using >, <, = and explain why with a model or place-value reasoning.