Are the following pair of sets equal ? Give reasons.

$A = \{ x:x$ is a letter in the word ${\rm{FOLLOW }}\} $

$B = \{ y:y$ is a letter in the word $WOLF\} $

Write the following sets in roster form :

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

$A = \{ x:x \ne x\} $ represents

State which of the following sets are finite or infinite :

$\{ x:x \in N$ and $x$ is odd $\} $

If $A = \{ 1,\,2,\,3,\,4,\,5\} ,$ then the number of proper subsets of $A$ is

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\varnothing \in A$