this is the dumbest question I've ever come up with, but I can't answer it, so that would make me horribly stupid. Why is: -1*-1=1 1*1=1 -1*1=-1 1*-1=-1 why can't: -1*-1=-1 1*1=-1 -1*1=1 1*-1=1 ? Is there any reason why we've defined things in the latter way rather than the former? p.s. sorry folks, I'm sure there is an obvious and simple reason, but I can't see it right now.