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

$\{ 2,3,4\}  \ldots \{ 1,2,3,4,5\} $

What universal set $(s)$ would you propose for each of the following :

The set of right triangles

Consider the sets

$\phi, A=\{1,3\}, B=\{1,5,9\}, C=\{1,3,5,7,9\}$

Insert the symbol $\subset$ or $ \not\subset $ between each of the following pair of sets:

$B \ldots \cdot C$

Write the following as intervals :

$\{ x:x \in R,3\, \le \,x\, \le \,4\} $

Which of the following are sets ? Justify your answer.

The collection of all natural numbers less than $100 .$

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