The number of non-empty subsets of the set $\{1, 2, 3, 4\}$ is

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

$10 \, .........\, A $

Write the following sets in the set-builder form :

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

State which of the following sets are finite or infinite :

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

Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?

For an integer $n$ let $S_n=\{n+1, n+2, \ldots \ldots, n+18\}$. Which of the following is true for all $n \geq 10$ ?