Question

Write the following set in set builder form.

The set of all prime numbers less than $100$.

Answer 1

Prime numbers less than $100$ are:

$2,3,5,7,11,....,97$

which can be written as $x$ is a prime number which is less than $100$.

Let A be the set of all prime numbers less than $100$.

Therefore, $\mathbf{\text{A =}}\mathbf{\{}\mathbf{x}\mathbf{:}\mathbf{}\mathbf{x}\mathbf{}\mathbf{\text{is a prime number}}\mathbf{,}\mathbf{}\mathbf{x}\mathbf{<}\mathbf{100}\mathbf{\}}$.