# Lesson 11

Libras y onzas

### Lesson Purpose

The purpose of this lesson is for students to make sense of the relative size of pounds and ounces and to express pounds in terms of ounces.

### Lesson Narrative

In previous lessons, students worked with metric units for length, weight, and capacity. Students may have encountered pounds and ounces in various contexts in or outside the classroom. Students may know that pound is the larger unit of the two. This lesson helps students develop a sense of 1 pound as 16 times as heavy as 1 ounce and to use this insight to convert pounds to ounces.

• Representation
• MLR8

### Learning Goals

Teacher Facing

• Describe the multiplicative relationship between pounds and ounces.
• Express pounds in terms of ounces.

### Student Facing

• Exploremos medidas en libras y en onzas.

### Required Materials

Materials to Copy

• Pounds and Ounces

### Required Preparation

Activity 1:

• Create a set of cards from the blackline master for each group of 4.
• If possible, gather examples of packaged food items—one that is labeled “1 ounce” and another labeled “1 pound”.

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

In an earlier section, students learned to represent and compare pairs of quantities in terms of multiplication. In what ways did you see their current knowledge of multiplicative comparison help or hinder them in performing unit conversions?

### Suggested Centers

• Would You Rather? (2–5), Stage 2: Compare to Smaller Units (Addressing)
• Compare (1–5), Stage 3: Multiply within 100 (Supporting)