Equality of Sets
Equality of sets is defined as set is said to be equal to set if both sets have the same elements or members of the sets, i.e. if each element of set also belongs to each element of set , and each element of set also belongs to each element of set .
Mathematically it can be written as and . In this case we write it as . If there is at least one elements of which is not in , then is not equal to and we write .
Example:

Let and , then because each element of set that is is equal to each element of set ; that is . If we rearrange the elements of the set it will remain the same.

Let and , then .