MathPrepAI
Sign up

Sum of Cubes

Add up the cubes, and you get a square number — build it one cube at a time and see why.

✓ Free to use

Can 15 × 15 squares be filled by cubes exactly?

Pour the cubes in one at a time and find out.

Cube 1 is about to be cut into 1 blocks of 1 × 1.

Add your name and logo to the board on any paid plan.

How many cubes

Build up to
5

The board is 15 × 15 = 225 squares.

Build

Speed

0 of 5 cubes poured

Show

Projector

Theme

More themes on any paid plan.

Your branding

Add your name and logo to the board on any paid plan.

Using it in class

  1. Ask first: can a pile of cubes ever make a perfect square?
  2. Pour one cube at a time and read the two lines aloud together.
  3. Stop after each cube and ask what the side of the filled square is — it is always 1 + 2 + … + k.
  4. For an even cube, point out the two half blocks and ask what they make between them.