Lesson objective: Identify regular and irregular quadrilaterals.

This lesson helps to build procedural skills with identifying quadrilaterals. Irregular shapes are used here because it supports students' understanding of defining attributes. This work develops students' understanding that quadrilaterals are closed, 2D shapes with four sides and four angles.

Students engage in Mathematical Practice 3 (Construct viable arguments and critique the reasoning of others) as they determine which shapes are quadrilaterals and discuss their decisions with their partners.

**Key vocabulary:**

**Special materials needed:**

- game pieces (prepared ahead of time)