School themed matchbox - Math

USA only. This is going along with my other matchbox swap, the science one. I also teach math, so here is the second in my school theme matchbox series. For this matchbox, you will do a math themed box. These are a few of my ideas, but please don't be boxed in by my ideas.

Algebra - numbers, letters, symbols, lines, graph paper

Geometry - shapes, circles, pi, graphs

Calculus - curves, elipses, more graphing

Sound good? Again, other than stickers, I don't know what kinds of things would be appropriate for filling. So, if you can't find stuff to fill the matchbox with, send an extra goodie outside, like a protractor or a compass. I reserve the right to ban for whatever reason. Thanks for swapping!