Definition of Sets

Definition of Sets

A set is just a group of things that we have picked out because they follow a clear rule.

Set is the collection of well-defined objects.

This means if you look at an object, you can easily tell if it belongs inside that group or if it stays outside.

The things you put inside a set are called elements or members of the set.

A set can have a limited number of things inside it, or it can go on forever without ending.

Example of a set

Let us look at this group of numbers: A = { 3, 6, 9, 12, 15, . . . }.

In this example, the numbers 3, 6, 9, 12, and 15 are the elements or members of the set called A.

Note on the three dots

The three dots at the end of the numbers mean that the list continues forever.

Note: … (the three dots) means infinity.

It shows that the set does not have an end.