Equality of sets – Sets

Let A be the set of all even natural numbers less than 10 and B be the set of natural numbers less than 10 which are not odd. Then A = {2, 4, 6, 8} and B = {2, 4, 6, 8}. Note that every element of B is also an element of A and every element of A is also an element of B. In such cases A and B are called equal sets.