> Why does functional programming have to be about math? You've misunderstood the GP's point. It's not that FP is about math, it's that you want to emphasize

> Why does functional programming have to be about math? You've misunderstood the GP's point. It's not that FP is about math, it's that you want to emphasize mathematical functions -- functions that don't rely on inputs other than their parameters and return values in a consistent co-domain. This is just good style to improve testability and minimize sources of potential bugs.