Lesson 13

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.”

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.

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?