Square Numbers, Square Pyramid

####Square Numbers, Square Pyramid, Sum of Square Numbers

These square pieces are made at the request of a classroom teacher. I flattened the sphere at the top and bottom for easy printing. Square numbers, including its connections with odd numbers, are appealing ideas in K-8. The sum of the first m odd numbers is always m^2. For example, 1 + 3 + 5 =3^2. Square numbers, when modeled using physical objects, can be placed on top of each other for a square pyramid, which shows the sum of the first few square numbers. Indeed, the sum of the first *n* square numbers has an interesting algebraic representation/function: sum of the first n square numbers=*n(n+1)(2n+1)/ 6*. When *n=5*, the sum is *55*. One can go as far as one likes or wherever the children are comfortable with these ideas. Do remember to review them across the grades.

#### Among the Files

1. Regular version: Sphere diameter is 12 mm. Of course, these can be scaled up or down.
2. Big version: Spher