Generally speaking, a function is a "subprogram" that can be called by code external (or internal, in the case of recursion) to the function. Like the program itself, a function is composed of a sequence of statements called the function body. Values can be passed to a function as parameters, and the function will return a value....expects the num parameter to be a number — although this is not enforceable...the formatNumber(2) call, the number 2 is the function's argument...