In previous grades, students learned that they can count the number of square tiles that cover a plane shape, without gaps or overlaps, to find the area of the shape. In this lesson, students explore the concept of volume as they build and compare objects made of cubes. Students learn that objects can have different shapes but take up the same amount of space, and that we call this space an object’s ‘volume.’

In the next lesson, students use unit cubes to find the volume of different objects. This work builds a conceptual understanding of volume before the introduction of formal ways to calculate the volume of a rectangular prism.
In lessons with images of objects made of cubes, students may question if the objects are missing cubes they can’t see. In these cases, tell students to assume the objects, including prisms, are completely packed with cubes.

Consider taking a community walk and noticing buildings and objects that are shaped like rectangular prisms in the community where your student’s live. In future lessons, you can display a list of these buildings and objects, and ask students to add to the display.

Math Community
In the Lesson Synthesis, students discuss what it means to be a part of a mathematical community. Prepare a space, such as a piece of chart paper, titled “Math Community,”​ ​and a T-chart with the headers “Doing Math” and “Norms.”​ ​Partition each column into two sections: “Students” and “Teacher.” The two sections encourage students and the teacher to be mindful that both respective parties are responsible for the way math is being done in the classroom. In this lesson, students will add their ideas to the “Doing Math”​ section. In upcoming lessons, students will add to and revise their contributions, including drafting classroom norms.

Who participated in math class today? What assumptions are you making about those who did not participate? How can you leverage each of your student’s ideas to support them in being seen and heard in tomorrow’s math class?