math. + Design.
When talking about design and math I think about the concept of pattern making in fashion design. When creating a certain pattern, you have to think about the measurements as well as the fit. That takes some math skills to figure out. On every pattern that you buy, they all have 2-5 lines on the outside for you to cut out. Those are for your measurements. The measurements on these patterns are not the same numbers that you measured yourself with. Instead you would have to take that number and put your math skills to use to figure out what your size is.
This also applies to when you want to alter your clothes or your patterns. When you buy a top or bottom at a mall, it will never fit you perfectly. No garment will ever fit a person perfectly if you bought it at a store. It will always needs some kind of altering, however people don't bother because its usually unnoticeable. To alter your clothes, that would require measurements <- math. Designing in all areas require some type of math to finish the piece perfectly. Just as math is required for clothing design to make sure it fit’s a person the way its supposed to.