Functional decomposition is a method of analysis that dissects a complex process to show its individual elements.

Here we look at a function as a mapping diagram. The inputs to the function g are along the real number line a the top, the outputs of g are on the real number line in the middle. The green point A ...

ELVIN RASOF, The fundamental principle of counting, tree diagrams, and the number of divisors of a number (the nu-function), The Arithmetic Teacher, Vol. 16, No. 4 (APRIL 1969), pp. 308-310 ...