Hi!

Here is the answer to your query.

In **set builder form**, the set is described by a characterizing property of its elements. In order to describe a set, a variable, say *x* is written inside the braces and then after putting a colon the common property* P* (*x*) possessed by each element of the set is written within the braces.

**Example:**

The set *P* = {1, 2, 3, 4, 5, 6, 7, 8} can be written in set builder form as *P* = {*x*: *x* ε N, *x* ≤ 8}

The set *Q* = {1, 4, 9, 16... 100} can be written in set builder form as *Q* = {*x* ^{2}: *x* ε N, 1 ≤ *x* ≤ 10}

In **roster form**, the set is described by listing elements, separated by commas, within the braces { }.

**Example:**

Let A = {*x*: *x* is a set of even natural numbers between 15 and 45} .Write this set in roster forms.

A = {*x*: *x* is a set of even natural numbers between 15 and 45}.

The roster form of this set can be written as:

A = {16, 18 20 22, 24 26, 28, 30, 32, 34, 36, 38, 40, 42, 44}

Cheers!