Here are some squares:

This square is 1 little square long and 1 little square wide. It has 1 little square inside it.

This square is 2 little squares long and 2 little squares wide. It has 4 little squares inside it.

This square is 3 little squares long and 3 little squares wide. It has 9 little squares inside it.

Here is the next square:

How many little squares are inside it?

What does the next square look like? How many little squares will there be inside it? I draw a square with 81 little squares inside it. How long and how wide is my square?