All vs. Only Some

All shapes have certain defining attributes that set them apart from others. In order to understand this, young mathematicians look at examples and non-examples of triangles, rectangles, and squares, working as a whole class to create definitions of each shape. To demonstrate their understanding of these new definitions, children are given a worksheet and asked to color a series of shapes according to their classification. This resource would serve perfectly as the introductory lesson plan to a primary grade geometry unit.