The elements of sets are

6× 1 = 6

3× 2 = 6

{1, 2, 3, 6} is a set of natural numbers and divisor of 6

6× 1 = 6

2 × 3 = 6

The divisors of 6 are 1, 6, 2 and 3 out of which 2 and 3 are prime

{2, 3} is the set of prime numbers which are divisor of 6

There are 11 letters in the word MATHEMATICS out of which 3 (M, T, A)are repeating .

{M, A, T, H, E, I, C, S} is a set of letters of the word MATHEMATICS

Natural numbers are 1, 2, 3, 4, 5, 6, 7, 8, 9,…………..

Odd numbers less than 10 are 1, 3, 5, 7, 9

{1, 3, 5, 7, 9} is a set of odd natural numbers less than 10