(i) Let A = {3, 6, 9, 12} All elements of the set are natural numbers that are multiples of 3. ∴ A = {x : x = 3n, n ∈ N and 1 ≤ n ≤ 4} (ii) Let B = {2, 4, 8, 16, 32} = {$2^1, 2^2, 2^3, 2^4, 2^5$} ∴ B = {x : x = $2^n$, n ∈ N and 1 ≤ n ≤ 5} (iii) Let C = {5, 25, 125, 625} = {$5^1, 5^2, 5^3, 5^4$} ∴ C = {x : x = 5n, n ∈ N and 1 ≤ n ≤ 4} (iv) Let D = {2, 4, 6, .......} All elements of the set are even natural numbers. ∴ D = {x: x is an even natural number} (v) Let E = {1, 4, 9, .........., 100} All elements of the set are perfect squares. ∴ E = {x: x = $n^2$, n ∈ N and 1 ≤ n ≤ 10}