future karmagisa where nagisa still has in mind that karma is like super good at math (and while is a genius that doesn't mean that grownups know basic formulas still in their 20s unless they're a teacher) so while nagisa talks to him about math he's teaching at school he's like uh huh uh huh sure babe i totally get it <--doesn't remember high school level math. and nagisa still asks karma to help him review stuff for lessons he's gonna do and karma is looking up on google trigonometry on his lunch break to keep up the image