In previous lessons, students used the layered structure to determine the volume of a rectangular prism that was filled with cubes. The purpose of this lesson is to extend their understanding of the structure of rectangular prisms by conceptualizing a base layer in a rectangular prism and utilizing it to find the volume in a fully or partially filled prism. Students connect the layered structure to multiplication when they write and interpret expressions that represent the volumes of rectangular prisms (MP2, MP7). This is a conceptual way for students to make sense of the associative property of multiplication. Students do not, however, need to name or identify the property.

Math Community
Before the lesson, explain to students that norms are expectations that help everyone in the room feel safe, comfortable, and productive doing math together. Offer an example, such as “It may help us share our ideas as a whole class if we have the norm ‘Listen as others share their ideas.’” Tell students to think about norms that help everyone do math as they work today, and that you will record these norms during the Lesson Synthesis.

This lesson has a Student Section Summary.

In the upcoming section, students will connect multiplying the area of the base and the height to multiplying all three side lengths when finding volume. Based on this lesson, what understandings do your students now have that will allow them to make that connection?