I can understand why the week's theme has fewer submissions. Maths puts many people off, and finding the fun in numbers can be challenging. Some of my feedback was that the equations I had chosen, "x+y*z=N", were too hard, yet in my head, I was thinking about equations like "x+ y + z*z = N". I think the other issue was that them numbers are very symbolic; different themes are more imaginary or emotional to them.