what is set ?

A set is a welldefined collection of objects. Sets are usually represented by capital letters A, B, C, D, X, Y, Z, etc.


The objects inside a set are called elements or members of a set. They are denoted by small letters a, b, c, d, x, y, z, etc.
 If a is an element of a set A, then we say that “a belongs to A” and mathematically we write it as “a ∈ A”; if b is not an element of A, then we write “b ∉ A”. E.g. If Z is a set of all integers, then 5 ∈ Z but 0.6 ∉ Z.
