This is just a grid that you'll be drawing all sorts of cool math things on -- like lines.

Remember our old number line?

a number line

Well, now we're going to do this in two directions -- make that two dimensions!

Check it out:

the rectangular coordinate system ... the horizontal line is the x-axis and the vertical line is the y-axis.

Think of it as a floor -- a two dimensional plane that you can draw stuff on.