Lesson objective: Decompose and recompose solid figures by partitioning figures into layers

This lesson helps to build procedural skill with finding volume of solid figures. Rectangular prisms and irregular figures are used here because it allows students to practice decomposing and recomposing figures in different ways. This work develops students' understanding that a** **solid figure which can be packed without gaps or overlaps using n unit cubes is said to have a volume of n cubic units.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they decompose and recompose geometric figures to make sense of spatial structure of volume.

**Key vocabulary:**

- decompose
- recompose
- partition
- solid figure
- irregular figure
- vertical layer
- horizontal layer
- base

**Special materials needed:**

- unit cubes