Lesson objective: Decompose figures to find the total area.

This lesson helps to build procedural skill with decomposing figures to find areas. Drawing a diagram is used here because it supports students’ ability to visualize the process. This work develops students' understanding that area is additive, meaning the area of a figure is the same as the sum of the area of non-overlapping regions of the figure.

Students engage in Mathematical Practice 4 (Model with mathematics) as they view, manipulate, and create models to represent decomposing the figures.

**Key vocabulary:**

**Special materials needed:**

- Graph paper may be helpful for some students.