Definition of Set:
            Set is a well defined collection of distinct objects (i.e. The nature of the object is the same or in other words object in a set may be any thing: number, people, place, letters etc.)
These objects are called the elements or members of the sets.

Notation:
            Set is usually denoted by capital letters  etc, and its elements are denoted by small letters etc.
            If “” is any set and “” is the element of set. Then we write  Read as “ belongs to ”.      If “” is any set and “” is not the element of set. Then we write  Read as “ belongs to ”

Representation of Sets:
            There are three ways to represents a set
(I) Tabular Form:
            Listing all the elements of a set, separated by commas and enclosed within curly brackets {}. e.g.
           
           
           
(II) Descriptive Form:
            State in words the elements of a set.
e.g.
            Set of the first five natural numbers.
            Set of positive even integers les or equal to fifty.
            Set of positive odd numbers.

(III) Set Builder Form:
            Writing in symbolic form the common characteristic shared by all the elements of the sets. e.g.