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\} $
Which of the following are sets ? Justify your answer.
The collection of questions in this chapter.
Write the following sets in roster form :
$\mathrm{F} =$ The set of all letters in the word $\mathrm{BETTER}$
Write the following sets in roster form :
$C = \{ x:x{\rm{ }}$ is a two-digit natural number such that sum of its digits is $8\} $
If a set $A$ has $n$ elements, then the total number of subsets of $A$ is