Which of the following are examples of the null set
$\{ x:x$ is a natural numbers, $x\, < \,5$ and $x\, > \,7\} $
Write the following intervals in set-builder form :
$\left( { - 3,0} \right)$
Which of the following are sets ? Justify your answer.
A collection of novels written by the writer Munshi Prem Chand.
Write down all the subsets of the following sets
$\{ 1,2,3\} $
Which of the following are sets ? Justify your answer.
The collection of all boys in your class.