Lesson 2

Fluency Flip

Lesson Purpose

The purpose of this lesson is for students to fluently add and subtract within 20 to find unknown addends.

Lesson Narrative

In previous lessons, students assessed their fluency with sums and differences within 20. They shared different methods for finding the value of sums and differences mentally.

In this lesson, students find unknown addends within 20 and continue developing fluency with addition and subtraction within 20.

The cool-down should be completed before the lesson synthesis so that students can share their responses during the lesson synthesis.

  • Engagement
  • MLR7

Learning Goals

Teacher Facing

  • Fluently add and subtract within 20.

Student Facing

  • Let’s add and subtract fluently.

Required Materials

Materials to Gather

Materials to Copy

  • Number Mix Up
  • Number Cards 0-19

Required Preparation

Activity 1:

  •    Create a set of cards for each group of 2.

Activity 2:

  • Each group of 2 needs the digit cards 09 from the card set used in the previous activity.

CCSS Standards


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

Think about which students haven’t shared their strategies in class lately. Were there missed opportunities to highlight their thinking during recent lessons? How can you take advantage of those opportunities when they arise?

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

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