Write the following sets in roster form :

$\mathrm{F} =$ The set of all letters in the word $\mathrm{BETTER}$

$F =$ The set of all letters in the word $BETTER$

There are $6$ letters in the word $BETTER,$ out of which letters $E$ and $T$ are repeated.

Therefore, this set can be written in roster form as

$F=\{B, E, T, R\}$

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, - 12\, < \,x\, < \, - 10\} $

Which of the following is the empty set

Given the sets $A=\{1,3,5\}, B=\{2,4,6\}$ and $C=\{0,2,4,6,8\},$ which of the following may be considered as universal set $(s)$ for all the three sets $A$, $B$ and $C$

$\{ 1,2,3,4,5,6,7,8\} $

If $Q = \left\{ {x:x = {1 \over y},\,{\rm{where \,\,}}y \in N} \right\}$, then