# Lesson 13

Situations Involving Equal-size Groups

### Lesson Purpose

The purpose of this lesson is for students to solve division problems in context, and to recall the two meanings of division: “how many in each group” and “how many groups.”

### Lesson Narrative

In grade 3, students learned about the relationship between multiplication and division and reasoned about division in terms of equal groups. They also saw two interpretations of division: as a way to find the size of a group and as a way to find the number of groups. They used these understandings to find quotients and to reason about division problems in context, finding whole-number quotients from two-digit dividends and one-digit divisors.

In this lesson, students build from the skills and ideas learned in grade 3 as they recall strategies for reasoning about division problems in context (MP2). Students encounter situations that involve equal-size groups and that call for finding the size of a group and the number of groups. The work here prepares students to rely on the relationship between division and multiplication to solve problems involving three-digit dividends in the next lesson.

• Action and Expression
• MLR2

### Learning Goals

Teacher Facing

• Reason about division of two- and three-digit numbers in situations involving equal-size groups.

### Student Facing

• Let’s interpret and solve division problems.

Building On

Addressing

### Lesson Timeline

 Warm-up 10 min Activity 1 15 min Activity 2 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

How readily did students see equal-size situations in terms of division (and see division expressions in terms of equal-size groups)? If they struggled to make a connection, what might be challenging?

### Suggested Centers

• Five in a Row: Multiplication (3–5), Stage 3: Two-digit Factors (Addressing)
• Compare (1–5), Stage 4: Divide within 100 (Supporting)

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### Additional Resources

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