Huh? you need to work on your operator precidence.
Division before subtraction.

3 sides
180 - 360/3 = 180 -120 = 60

4 sides
180 - 360/4 = 180 - 90 = 90

5 sides
180 - 360/5 = 180 -72 = 108

6 sides
180 - 360/6 = 180 - 60 = 120

The formula is based on the fact that the external angles add up to 360 degrees, and the internal angle is 180 - the external angle.
Clearly the formula goes wrong for n=1 or n=2, but those are not valid shapes anyway.

Firstly of course they are directly competing for volanteer time and resources. Secondly the inherent desire to "be the best", and to prove that their solution is the best one.

And since when do people need a good reason for being competive?