Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{\varnothing\} \subset A$
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\} $
Which of the following are examples of the null set
$\{ y:y$ is a point common to any two parallellines $\} $
Which of the following sets are finite or infinite.
The set of months of a year
List all the subsets of the set $\{-1,0,1\}.$