Lesson 4

Problemas-historia con cambio desconocido

Lesson Purpose

The purpose of this lesson is for students to solve Add To and Take From, Change Unknown story problems.

Lesson Narrative

In a previous unit, students were introduced to Add To and Take From, Change Unknown story problems and solved these problems in any way that made sense to them. This lesson offers more practice making sense of and solving these types of problems. Students share different methods used and discuss how either addition or subtraction can be used to solve these problems. These discussions help students develop their understanding of how to make sense of and solve these problem types and reinforce their methods for adding and subtracting within 20.

If students need additional support with the concepts in this lesson, refer back to Unit 2, Section A in the curriculum materials. 

  • Representation
  • MLR8

Activity 2: Encontremos el número desconocido

Learning Goals

Teacher Facing

  • Solve Add To and Take From, Change Unknown story problems in a way that makes sense to them.

Student Facing

Resolvamos problemas-historia.

Required Materials

Required Preparation

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 times when students were able to make connections to and build on the ideas of their peers during discussions today. What norms or routines allowed students to engage with other students’ ideas?

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