If you haven't done so already, make a simple world for yourself where you can explore mathematical concepts without messing up anything you've created in your other worlds.

Make a series of rectangles that meet the following descriptions:

- A 2x3 grid of blocks.
- A 3x5 grid of blocks.
- A 7x10 grid of blocks.
- A 10x12 grid of blocks.

How many blocks are in each of these rectangles?
Do you know what people call this calculation in math?