The number of proper subsets of the set $\{1, 2, 3\}$ is
$8$
$6$
$7$
$5$
Write the following sets in roster form :
$D = \{ x:x$ is a prime number which is divisor of $60\} $
Write the following intervals in set-builder form :
$\left( { - 3,0} \right)$
Let $A, B$ and $C$ be three sets. If $A \in B$ and $B \subset C$, is it true that $A$ $\subset$ $C$ ?. If not, give an example.
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{ 3,4\} \subset A$
The smallest set $A$ such that $A \cup \{1, 2\} = \{1, 2, 3, 5, 9\}$ is