If $A$ and $B$ are any two non empty sets and $A$ is proper subset of $B$. If $n(A) = 4$, then minimum possible value of $n(A \Delta B)$ is (where $\Delta$ denotes symmetric difference of set $A$ and set $B$)

Which of the following sets are finite or infinite.

The set of positive integers greater than $100$

State whether each of the following set is finite or infinite :

The set of numbers which are multiple of $5$

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

$ 0\, ........\, A $

Write the set $\{ x:x$ is a positive integer and ${x^2} < 40\} $ in the roster form.

Make correct statements by filling in the symbols $\subset$ or $ \not\subset $ in the blank spaces:

$\{ x:x$ is an even natural mumber $\}  \ldots \{ x:x$ is an integer $\} $