Write the following intervals in set-builder form :

$\left( { - 3,0} \right)$

Write down all the subsets of the following sets

$\{ a,b\} $

Which of the following are sets ? Justify your answer.

The collection of all natural numbers less than $100 .$

Write the following as intervals :

$\{ x:x \in R,3\, \le \,x\, \le \,4\} $

Write down all the subsets of the following sets

$\{ a\} $

In the following state whether $A=B$ or not :

$A=\{a, b, c, d\} ; B=\{d, c, b, a\}$