What is a Geometry Sort? A geometry sort is when students are classifying shapes into categories based on the geometric attributes of those shapes.

Why Use Geometry Sorts to Teach Geometric Attributes?

-Geometry sorts help students focus on the identifying geometric attributes (number of sides, parallel lines, angle sizes), as opposed to other attributes such as color, orientation, and shape size.

-Geometric attribute sorts help students look for and notice patterns among shapes with a common attribute. They may notice that all rectangles also have two sets of parallel sides, for example.

-Sorts challenge and push student thinking about classifying shapes. Does a square go in the “rectangle” or “not a rectangle” category?  Challenging thinking like this helps students expand their understanding of what a rectangle is, and helps them see squares as a subset of rectangles, rather than a separate category. It helps them see that not all rectangles look a certain way.

-Once students have classified the shapes into categories, they can draw additional shapes that fit each category. This pushes their thinking about geometric attributes even further.

–I teach Geometry at the beginning of the school year, because I believe it sets the students up for success the rest of the year in the other math strands. And classifying is a big part of that, because it helps students identify what’s important and what’s not, look for patterns, and more deeply understand how math concepts relate to each other.

Types of Geometric Attribute Sorts:

(Listed in order from simplest to most complex.)
1. In/ Out (example/ nonexample): Students classify shapes into two categories. The shape either has the geometric attribute or it doesn’t.Example: polygon/ not polygons

2. Mutually Exclusive Groups:
Students classify shapes in to two or more mutually exclusive categories. Each shape can only fit into one category based on its geometric attributes.
Example: classifying triangles by number of equal sides

3. Side-by-Side Sorts:
Students classify the same set of shapes into two different sets of categories, so they can compare and contrast the two different classifications.
Example: sort triangles by angle size, and then sort them by side length

4. Venn Diagram:
Students classify shapes onto a Venn Diagram so they can see the geometric attributes they have in common.
Example: comparing and contrasting the geometric attributes of a rhombus and a rectangle

5. Overlapping Circles (Hierarchy):
Students classify shapes into overlapping circles. The largest circle represents the largest category of attributes (e.g., polygons), and the smallest circle represents the smallest/ most specific category of geometric attributes (e.g., squares). This way of classifying is more complex because students have to consider subgroups and the hierarchy of attributes.
Example: polygons/ quadrilaterals/ parallelograms/ rectangles/ squares

Discussion Questions about Classifying Shapes:

-What geometric attribute makes this a ____ ?
-How do you decide how to classify a shape?
-Why did you put this shape in this category?
-How could you change this shape so it would go in a different category?
-What geometric attribute do all the shapes in this category have in common? Do they also have anything else in common?
-What would you call this shape? Why? Could you call it anything else?
-What geometric attribute would a shape need to be in this category?
-Are there any geometric attributes that would keep a shape OUT of this category?
-How are ___ and ___ related?
-Do the shapes in these two different categories have any geometric attributes in common? Are these subcategories of a bigger category?

Happy Teaching (& Sorting)!!
 Christine Cadalzo 

PS: Looking for some pre-made, Common Core- aligned sorts, lessons, and activities?
Click here for my:
Second Grade Geometric Attributes Unit
Third Grade Geometric Attributes Unit
Fourth Grade Geometric Attributes Unit