# Lesson 13

Divide Whole Numbers by Unit Fractions

### Lesson Purpose

The purpose of this lesson is for students to solve division problems in a way that makes sense to them.

### Lesson Narrative

In this lesson students investigate dividing a whole number by a unit fraction using the context of strips of paper. In the warm-up, they describe what they notice and wonder about a picture of a quilt. During Activity 1, they consider cutting paper strips and using the strips to make a paper quilt. In Activity 2, as they did for division of a unit fraction by a whole number, students use a tape diagram which has the additional advantage of resembling the strips of paper. They observe how the quotient depends on the size of the dividend and represent the quotient with an equation. It may be helpful for students to actually make paper quilts. If possible, cut 2 foot length pieces of construction paper in various colors before the lesson and ask students to follow the directions in the problem prompts to make smaller pieces of each color. After the lesson, students can use the pieces to create a paper quilt.

• Representation

### Learning Goals

Teacher Facing

• Divide a whole number by a unit fraction in context, in a way that makes sense to them.

### Student Facing

• Let’s divide a whole number by a unit fraction.

### Required Materials

Materials to Gather

### Required Preparation

If students will be making My Way quilts, create 2 foot long pieces of construction paper in red, yellow, and green.

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 students think about division as they came into the lesson? In what ways did their understanding of division change upon completing the lesson?

### Suggested Centers

• Rolling for Fractions (3–5), Stage 4: Multiply Fractions (Addressing)
• Compare (1–5), Stage 4: Divide within 100 (Supporting)
• How Close? (1–5), Stage 7: Multiply Fractions and Whole Numbers to 5 (Supporting)