# Lesson 3

Separemos los cubos

### Lesson Purpose

The purpose of this lesson is for students to find multiple decompositions of a number and look for patterns in decompositions.

### Lesson Narrative

In previous lessons, students have composed and decomposed numbers and noticed that numbers can be composed and decomposed in more than one way. In this lesson, students decompose numbers in more than one way. In the first activity, students do this by snapping a tower of connecting cubes into 2 parts in different ways. In the second activity, students are given a written number rather than objects. Decomposing a number into parts in different ways deepens their understanding of numbers and their relationships (MP7).

• Action and Expression
• MLR8

### Learning Goals

Teacher Facing

• Compose and decompose numbers up to 9.

### Student Facing

• Encontremos diferentes maneras de separar números.

### Required Materials

Materials to Gather

Materials to Copy

• What's Behind My Back Stage 1 Recording Sheet, Spanish

### Required Preparation

Activity 1:

• Each group of 2 needs 8 connecting cubes of the same color.

Activity 3:

• Gather materials from:
• What’s Behind My Back?, Stage 1
• Check It Off, Stage 1
• Find the Value of Expressions, Stage 1
• Bingo, Stages 1–3
• Shake and Spill, Stages 1–3

### Lesson Timeline

 Warm-up 10 min Activity 1 10 min Activity 2 10 min Activity 3 20 min Lesson Synthesis 5 min Cool-down 5 min

### Teacher Reflection Questions

In a future section, students will find more than one solution to a Put Together/Take Apart, Both Addends Unknown story problems. What do you notice in their work from today’s lesson that you might leverage in that future lesson?