What is a set?

A set is a collection of things. The "things" that are in the set can be made up of different objects. For example, a set of shapes or a set of pencils or pens. The things that make up a set are called elements or members.

The elements contained in the set shown below are shapes. In fact these are special shapes called polygons. 

We use special notation, brackets and symbols to describe sets. That is what we discuss next.