The complement of a set A (that is a subset of a universal set U) is defined as a set that contains all the member elements and all subsets of U that are not part of the set A. The complement of a set is denoted using the symbol ‘ or ^c.

Hence, A’ = A^c = complement of A

Example:-

If N is the universal set, and if A = { 1, 2,3 } then A’ = { x ∈ N | x >3 }

A = { set of all boys in a class }, then A’ ={ set of all girls in a class }

A = { set of all vowels in English language }, then A’ = { set of all consonants in English language }

A = { x ∈ N | x = 2x + 3 }, then A’ = { x ∈ N | x ≠ 2x + 3}

A Venn Diagram showing the complement of a set in graphic terms