# Lesson 17

Formemos 10 y separemos el 10 (optional)

### Lesson Purpose

The purpose of this lesson is for students to compose and decompose 10 in multiple ways.

### Lesson Narrative

In a previous unit, students composed and decomposed 10 in multiple ways using their fingers and 10-frames. This lesson is optional because it is an opportunity for practice that not all students may need. This lesson provides additional practice with compositions and decompositions of 10 before students find the number that makes 10 when added to a given number. Students create a tool with 10 beads, 5 in each color, that can be used in addition to a 10-frame and fingers to show different compositions and decompositions of 10. Students may choose to use this tool throughout the section.

If students need additional support with the concepts in this lesson, refer back to Unit 5, Section C in the curriculum materials.

• Representation
• MLR8

### Learning Goals

Teacher Facing

• Relate equations to different compositions and decompositions of 10.

### Student Facing

• Busquemos grupos que forman 10.

### Required Materials

Materials to Gather

### Required Preparation

Activity 1:

• Each student needs a pipe cleaner and 10 beads, 5 beads of one color and 5 beads of another color.

Activity 2:

• Each student needs the bead tool that they created in the previous activity.

Activity 3:

• Gather materials from:
• Shake and Spill
• Number Race
• Grab and Count
• What's Behind My Back?
• Pattern Blocks

### Lesson Timeline

 Warm-up 10 min Activity 1 10 min Activity 2 10 min Activity 3 25 min Lesson Synthesis 5 min Cool-down 0 min

### Teacher Reflection Questions

How is the bead tool that students made in this lesson similar to and different from other tools that they have used? How do you anticipate that students will use the bead tools in future lessons?