Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:

$ 8\, .......\, A $

Write the following sets in the set-builder form :

${\rm{\{ 2,4,8,16,32\} }}$

Which of the following are examples of the null set

Set of odd natural numbers divisible by $2$

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\{ \{ 3,4\} \}  \subset A$

Write the following intervals in set-builder form :

$\left[ { - 23,5} \right)$

If a set $A$ has $n$ elements, then the total number of subsets of $A$ is