# Lesson 9

### Lesson Purpose

The purpose of this lesson is for students to deepen their understanding that teen numbers are composed of a ten and some ones, and to find the value that makes an addition equation true when one addend is 10.

### Lesson Narrative

This lesson builds on the previous lesson in which students composed teen numbers using a ten and some ones. Students move from using connecting cube towers to filled-in 10-frames to represent teen numbers. Students also relate their composition work and the relationship between addition and subtraction to find values that make equations true.

Students continue using double 10-frames throughout the unit. Consider making copies on card stock so they can be used repeatedly.

• Representation
• MLR8

### Learning Goals

Teacher Facing

• Compose and decompose teen numbers into 1 ten and some number of ones.
• Find the value that makes an addition equation true, where one addend is 10.

### Student Facing

• Let's use a ten to make teen numbers.

### Required Materials

Materials to Gather

Materials to Copy

• Double 10-Frame - Standard
• Number Cards 11-20

### Required Preparation

Activity 1:

• Create a set of Number Cards (11-20)  from the blackline master for each group of 2.

### 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

What methods are students using when they build teen numbers: concrete objects on a 10-frame, drawings, numbers? How do these methods reflect their developing understanding of the unit ten?

### Print Formatted Materials

For access, consult one of our IM Certified Partners.