Lesson 3

Add and Subtract Within 20

Lesson Purpose

The purpose of this lesson is for students to add and subtract within 20.

Lesson Narrative

In previous lessons, students practiced adding and subtracting within 10. In this lesson, students use the methods that make the most sense to them to add and subtract within 20. The lesson activities encourage students to use methods such as using known facts, making 10 to add, decomposing a number to lead to a 10 to subtract, and using the relationship between addition and subtraction. This lesson helps students practice adding and subtracting with 20 and apply their fluency within 10 in preparation for their work with addition and subtraction in grade 2.   

If students need additional support with the concepts in this lesson, refer back to Unit 3, Sections C and D in the curriculum materials.

  • Engagement
  • MLR8

Activity 1: Many Ways to Add and Subtract

Learning Goals

Teacher Facing

  • Add and subtract within 20.

Student Facing

  • Let’s add and subtract within 20.

Required Preparation

CCSS Standards


Lesson Timeline

Warm-up 10 min
Activity 1 20 min
Activity 2 20 min
Lesson Synthesis 10 min
Cool-down 0 min

Teacher Reflection Questions

Reflect on your experience with the Number Talks in the curriculum. What moves or questions have improved the learning for each of your students during this routine? What improvements would you make next year to help all students develop fluency throughout the year?

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

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