Cardinality of union of three sets for JEE

Formula

\[ n(A \cup B \cup C) = n(A)+n(B)+n(C)-n(A\cap B)-n(B\cap C)-n(C\cap A)+n(A\cap B\cap C) \]

Variables: \(n(\cdot)\): number of elements in a set

Conditions: Finite sets \(A,B,C\)

Inclusion-exclusion in JEE Main set problems