Let’s solve some universal set examples and practice problems for better understanding. Solved Examples on Universal Set 1. Assuming P is the set of positive odd integers and Q is the set of positive even integers, write the universal set of P and Q. Solution: The sets P and Q can be written as: P = {1, 3, 9 …} Q = {2, 4, 6 …}

Examples (i) When we study two dimensional coordinate geometry, then set of all points in xy-plane in the universal set. (ii) When we using sets containing natural numbers, then N is the universal set. (iii) If A = {1, 2, 3}, B = {2, 4, 5, 6} and C = {1, 3, 5, 7}, then U = {1, 2, 3, 4, 5, 6, 7} can be taken as a universal set.