In art and in drawing it is common to use math. It could be as simple as measuring and making things symmetrical or complex things like tessellations. It's easy to forget or not even realize that you are doing math while drawing.
The Golden Ratio - 1.618
In art the golden ratio has been used for centuries, even dating back to Leonardo Da Vinci. It's only easy to see when a picture uses this ratio if you draw it out. The image to the right as an example.
Tessellations
Tessellations can be simply put as images repeated that continue to infinity. A bunch of cubes with the same measurements could be a tessellation. Sliding a 2d picture across a 2d plain in a copy and pasting motion is an easy way to picture tessellations.
made by William Taylor