Understanding the Inclusion-Exclusion Principle (Set Union Formula for Three-Set Functions)

Formula: | A ∪ B ∪ C | = | A | + | B | + | C | – | A ∩ B | – | A ∩ C | – | B ∩ C | + | A ∩ B ∩ C |
A represents Data Set A
B represents Data Set B
C represents Data Set C
A ∪ B represents the overlapping data sets
A ∩ C represents the overlapping data sets
B ∩ C represents the overlapping data sets
A ∩ B ∩ C represents the middle center overlapping data sets