Lesson 12

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Lesson Purpose

The purpose of this lesson is for students to solve Compare, Difference Unknown story problems in a way that makes sense to them.

Lesson Narrative

Students build on representations and methods they learned in the previous lesson, in which students compared different quantities of connecting cubes. In this lesson, students work with comparisons in story contexts. The first activity uses the Three Reads routine to help students better understand the story problem and how the quantities are related. 

As students explain their thinking, write equations to support connections between comparing and addition and subtraction. Include a box around the difference in the equations.

  • Representation
  • MLR7

Learning Goals

Teacher Facing

  • Relate counting to addition and subtraction.
  • Solve Compare, Difference Unknown story problems in a way that makes sense to them.

Student Facing

  • Encontremos la diferencia entre las cantidades.

Required Materials

Required Preparation

CCSS Standards


Building Towards

Lesson Timeline

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

Teacher Reflection Questions

How effective were your questions in supporting students’ thinking today? What did students say or do that showed they were effective?

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