Inclusion-Exclusion Principle: idea and how to use it
What is the Inclusion-Exclusion Principle? The Inclusion-Exclusion Principle may sound fancy but it is nothing more than a counting strategy. The Principle of Inclusion-Exclusion provides a method to find the size of the union of a group of sets, given the size of each set and the size of all possible intersections among the sets. To illustrate, we take a look at…