How do you translate into symbols: The difference between n and 14?
It depends on how exactly you interpet the idea of "difference".
If you speak in a merely numeric sense, then the difference between two numbers
Anyway, in a more general sense, maybe the absolute value is more adequate, since it computes "how far" two numbers are from each other, giving always a positive result. It seems more logic, because it says that
So, I'd say that the most proper answer is