Lesson objective: Understand that geometric shapes can be sorted and counted to identify how many are in a category.

Students bring prior knowledge of identifying 2D shapes and sorting from ability to count, sort, and categorize objects and also identify and describe shapes. This prior knowledge is extended to sorting and counting geometric shapes. A conceptual challenge students may encounter is recognizing similar attributes between shapes.

The concept is developed through work with geometric shapes, which will help students to recognize multiple measurable attributes.

This work helps students deepen their understanding of numbers because students will be counting how many shapes are in a group.

Students engage in Mathematical Practice 7: Look for and make use of structure. Mathematically proficient students are able to look closely and use structure to identify, describe, and create shapes as they sort and count geometric shapes.

**Key vocabulary:**

- attributes
- curved
- straight

**Special materials needed:**

- geometric blocks (attribute blocks, pattern blocks, etc.)