# Lesson 14

Ways to Represent Multiplication of Teen Numbers

### Lesson Purpose

The purpose of this lesson is for students to make sense of representations of the multiplication of teen numbers.

### Lesson Narrative

The work of this lesson connects to previous work because students have solved problems involving multiplication of teen numbers in ways that make sense to them. In the previous section they also used the distributive property to find products of single-digit factors using facts they know. In this lesson, students consider and connect different representations of a strategy used in the previous section that can also be used to multiply a teen number. This will be helpful in the next lesson when students solve these types of problems and choose how to represent the problem.

• Representation
• MLR8

Activity 1: A Factor Greater than Ten

### Learning Goals

Teacher Facing

• Make sense of representations of multiplication (base-ten blocks and area diagrams) where one factor is a teen number.

### Student Facing

• Let’s make sense of some ways to represent the multiplication of teen numbers.

### Required Materials

Materials to Gather

Building Towards

### 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

How did their previous work with area diagrams support students in their work today with multiplying teen numbers?

### Suggested Centers

• Compare (1–5), Stage 2: Add and Subtract within 20 (Supporting)
• How Close? (1–5), Stage 4: Add to 1,000 (Supporting)