2D Geometry

When investigating primary geometry, students are commonly only presented with ‘traditional’ shapes.  This limits their understanding of the properties of these shapes.

Shapes should be presented in varying orientations. Additionally, a variety of shape examples should be used. Young students need to see that not all triangles are equilateral. By seeing a range of shapes, they learn to recognize the properties of all triangles, not just equilateral triangles.

When comparing and sorting 2D shapes, a variety of non-standard shapes should be available. Commercial kits can be bought, but they can also be easily cut out of plastic or foamcore. Translucent binder covers from the dollar store are a good source of plastic, and they also work on the overhead.

For example, many teaching resources and children’s books always show triangles like this:


Non-Traditional Shape Templates

This is a set of about 2D shapes from the Guide to Effective Instruction. They’re spread a little too far apart for photocopying onto cardstock, and are all polygons – no curved edges.

What Shape Could It Be?
In this activity, the teacher reveals part of a shape until students can deduce the correct shape.

Commercial Non-Traditional Shapes

These shapes from Pearson are a good size, translucent for the overhead, and provide a great variety of shapes. Unfortunately expensive.

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