Write down all possible proper subsets each of the following sets :
(i) {1, 2} (ii) {1, 2, 3}
(iii) {1}
(i) We know that if A is a set and B a subset of A, then B is called a proper subset of A is B⊈A and B≠A, ϕ and is written asB⊂A or B⊈A.
Hence, the proper subsets are given by {1}, {2}.
(ii) The proper subsets are given by {1}, {2}, {3}, {1,2}, {2, 3}, {1, 3}.
(iii) The only subsets of the given set are ϕ and {1}.
Hence, there are no proper subsets.