In Kindergarten you counted sides and corners. Those are what make a shape a shape.
| Matters for the name | Does not matter |
|---|---|
| how many straight sides | color |
| how many corners | size |
| closed, with no gaps | which way it is turned |
Key idea
A shape’s name depends on its defining attributes: closed, straight sides, and how many sides and corners. Color, size and turning do not matter.
Why it works
If you paint a triangle blue or make it bigger, it still has 3 straight sides and 3 corners. That is what “triangle” means.
Worked example: Same kind?
Is a tiny blue triangle the same kind of shape as a big red triangle?
- Both are closed, with 3 straight sides and 3 corners.
- Yes: both are triangles.
Answer: Yes
Common mistake
Thinking a big red triangle and a small blue triangle are different kinds of shapes. Count sides and corners, and ignore color and size.
For grown-ups: Cut out shapes in different sizes and colors. Ask your child to sort them by shape, not by color.