Lesson objective: Find the area of an irregular figure.

This optional lesson helps to build procedural skills with finding the area of an irregular figure that students previously studied in Grade 3. Multiplication, addition, and subtraction are used as students integrate different operations to extend their understanding of area. This work develops students' understanding that the relationship between operations can be used to solve real world problems.

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they connect their previous knowledge of finding the area of a rectangle to the new skill of determining the area of irregular figures.

**Key vocabulary:**

- area
- inverse