List all the elements of the following sers :
$B = \{ x:x$ is an integer $; - \frac{1}{2} < n < \frac{9}{2}\} $
List all the subsets of the set $\{-1,0,1\}.$
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\} $
Which of the following are sets ? Justify your answer.
The collection of all even integers.
How many elements has $P(A),$ if $A=\varnothing ?$