# Sets

*set*is a collection of objects, and the objects are called

*elements*of the set. You may be asked to form the

*union*of two sets, which contains all the objects from either set. You may also be asked to form the

*intersection*of two sets, which contains only the objects that are in both sets.

For example, if Set

*A*= {1, 2, 5} and Set

*B*= {5, 10, 21}, then the union of sets

*A*and

*B*would be {1, 2, 5, 10, 21} and the intersection would be {5}.