Lesson 10

Add within 1,000

Lesson Purpose

The purpose of this lesson is for students to add three-digit numbers using strategies based on place value and the properties of operations.

Lesson Narrative

In previous lessons, students used properties of operations, their understanding of the count sequence, and their understanding of place value to add within 1,000. They used different methods and representations to add by place and compose tens and hundreds.

In this lesson, students choose their own methods for adding within 1,000 and share their methods with their peers. They also have opportunities to explain why they chose their methods based on the numbers in an expression. They also analyze the relationship between two numbers in an equation to find an unknown value. Students use what they know about composing units to find unknown three-digit numbers when they are partially covered.

  • Action and Expression

Learning Goals

Teacher Facing

  • Add numbers within 1,000 using strategies based on place value and the properties of operations.

Student Facing

  • Let’s find sums within 1,000 and explain our strategies.

Required Materials

Materials to Gather

Materials to Copy

  • How Did You Do That? Addition Card Sort

Required Preparation

Activity 1:

  • Create a set of cards from the blackline master for each group of 2. 

CCSS Standards

Building On


Lesson Timeline

Warm-up 10 min
Activity 1 20 min
Activity 2 15 min
Lesson Synthesis 10 min
Cool-down 5 min

Teacher Reflection Questions

Unlike talking, listening is a difficult thing to observe. At what points in the lesson did you observe students listening to one another’s ideas today in class? What indicators do you have that they were listening?

Suggested Centers

  • Five in a Row: Addition and Subtraction (1–2), Stage 7: Add within 1,000 without Composing (Addressing)
  • Number Puzzles: Addition and Subtraction (1–4), Stage 4: Within 100 with Composing (Supporting)

Print Formatted Materials

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Student Task Statements pdf docx
Lesson Cover Page pdf docx
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Teacher Presentation Materials pdf docx
Blackline Masters zip

Additional Resources

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