# Lesson 17

Cachorros y tulipanes (optional)

### Lesson Purpose

The purpose of this lesson is for students to use their understanding of addition and subtraction to solve Compare story problems.

### Lesson Narrative

This lesson is optional because it does not address any new mathematical content standards. This lesson does provide students with an opportunity to apply precursor skills of mathematical modeling. In this lesson, students make origami tulips and puppies and use problem sentence frames to tell puppy and tulip stories using “fewer” and “more”. Students solve Compare, Difference Unknown story problems with language that suggests the opposite operation. For example, problems that use a comparison statement with “more,” but require subtraction to solve. Students will work more with these problem types in grade 2.

When students make choices, adhere to constraints, and analyze real-world situations with mathematical ideas they model with mathematics (MP4).

• Action and Expression
• MLR8

### Learning Goals

Teacher Facing

• Analyze and solve Compare story problems with unknowns in all positions.
• Write equations to represent story problems.

### Student Facing

• Hagamos origami y, luego, contemos y resolvamos problemas-historia usando las palabras “más” y “menos”.

### Required Materials

Materials to Gather

Materials to Copy

• Origami Triangles: Puppies and Tulips

### Required Preparation

Activity 1:

• Each group of 2 needs at least 20 paper triangles.

Activity 2:

• Each group needs their origami stories from the previous activity.

Building Towards

### Lesson Timeline

 Warm-up 10 min Activity 1 25 min Activity 2 15 min Lesson Synthesis 10 min

### Teacher Reflection Questions

Think about a recent time from class when your students were confused. What did you do to support them in reasoning about their confusion together as a community of learners?