FPs generally allow functions to curry. A simple example would be an add function that takes two parameters - the values to be added:
   fun add x y = x + y\n\n   val x = add 10\n\n   val y = x 20

Notice that the calculation of the x value only calls the add function with one parameter (10). The result of this application is that x itself is a function that takes one value. Effectively it is the function:
fun x(y) = 10 + y

This concept of currying is part of the consideration for higher order functions.