A fraction or proportion in general doesn't have to be representable as a ratio of natural numbers. That's called a "common fraction", and as it happens, floati

A fraction or proportion in general doesn't have to be representable as a ratio of natural numbers. That's called a "common fraction", and as it happens, floating point representation stores the value as a ratio of natural numbers anyway. It's like asking someone to cut you 1/pi of a pie. It isn't total nonsense, but it is weird and you're going to get an approximation. They might get confused by your odd request and give you half a pie instead a third of a pie though!