# Shape Recognizer—Circles, Squares, and Triangles

## Sub Trajectory: Classifying

Recognizes some less typical squares and triangles and may recognize some rectangles, but usually not rhombuses (diamonds). May not distinguish between sides and corners. Differentiates between 2D and 3D shapes and recognizes faces of 3D shapes as 2D shapes.

### Other Examples:

• A child correctly names shapes with three straight sides as "triangles".
• A child correctly names shapes with four equal sides and four right angles as "squares".
• A child correctly names shapes that are perfectly round as "circles".

Activities and discussions invite children to name shapes that are common in the culture, circles and squares, and triangles. Include shapes that are less typical--that are turned different ways, as well as "long, skinny" triangles and so forth as soon as possible to give children rich, varied mental images of shapes.

Practice-based Research: Most early childhood math programs typically show only standard examples of shapes, such as an equilateral triangle with a horizontal base. Research shows, however, that such limited experience restricts and can even damage children’s development of geometric ideas. This program provides exposure "long, skinny" triangles, and turns all shapes to different orientations.

Triangles must have three straight lines and be closed. For example, a child sees a musical triangle, which typically has curved corners with one opening, and calls it a triangle; explain that, though it is triangular, it is not a true triangle based on the aforementioned attributes. Agree it is called a triangle and ask "How would you make that a mathematical triangle?"

Activities like Is It or Not? develop sorting and classifying abilities. Sorting by mathematical properties is perhaps the most important type of classifying activity. Children learn to sort by mathematical attributes in the same way they sort by other attributes, such as color, thus deepening their understanding of mathematical attributes. Children also learn that classifications of such attributes are an important aspect of mathematics. ##### Shape Hunt [Triangles] ##### Shape Show [Triangles] ##### Find the Twin [Circles, Triangles, Squares] ##### Is It or Not? (Triangles) ##### Is It or Not? (Circles) ##### Circles and Cans ##### Feely Box [Circles, Squares, Triangles] ##### Is It or Not? (Squares) ## Special Thanks To 