Lesson objective: Count geometric shapes and sort them into categories.

This lesson helps to build fluency with sorting and counting 2D shapes. Sortable shapes are used here because it supports the understanding that 2D shapes can be sorted by attributes. This work develops students' understanding that geometric shapes can be sorted and counted based on similar attributes.

Students engage in Mathematical Practice 3: Construct viable arguments and critique the reasoning of others. Mathematically proficient students will be able to apply their understandings of defining attributes to construct and critique sorting rules for shapes as they sort and count by geometic shapes based on a specific category.

**Key vocabulary:**

- attributes
- dotted
- solid
- sort

**Special materials needed:**