Write the following sets in roster form :
$\mathrm{F} =$ The set of all letters in the word $\mathrm{BETTER}$
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\} $
Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:
$10 \, .........\, A $
State which of the following sets are finite or infinite :
$\{ x:x \in N$ and $(x - 1)(x - 2) = 0\} $
If $A = \{ 1,\,2,\,3,\,4,\,5\} ,$ then the number of proper subsets of $A$ is