State which of the following sets are finite or infinite :

$\{ x:x \in N$ and ${x^2} = 4\} $

Which set is the subset of all given sets

Write the following intervals in set-builder form :

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

Write the following sets in the set-builder form :

$\{ 3,6,9,12\}$

Write down all the subsets of the following sets

$\{ a\} $

Set $A$ has $m$ elements and Set $B$ has $n$ elements. If the total number of subsets of $A$ is $112$ more than the total number of subsets of $B$, then the value of $m \times n$ is