Lesson 3

The purpose of this lesson is for students to find the volume of a rectangular prism using its layered structure.

In previous lessons, students built objects, including rectangular prisms, with unit cubes and counted the number of cubes. In this lesson, students continue to count the number of unit cubes needed to build a rectangular prism, but now they are presented with images of prisms instead of the objects themselves. To encourage students to develop a systematic way to count the cubes, they are shown prisms made from larger numbers of cubes. As students use horizontal or vertical layers to measure the volume, they make use of the layered structure of prisms (MP7).

Math Community

Tell students that, at the end of the lesson, they will be asked to identify specific actions from their “Doing Math” list (both teacher and student sections) they personally experienced.

• Create a set of cards from the blackline master for each group of 4.
• Each group of 2 needs 48 connecting cubes.

• Give students access to connecting cubes.

What connections did students make between the different strategies they used to build the prisms and determine the volume? What questions did you ask to help make the connections more visible?