Let $S=\{1,2,3,4\}$. The total number of unordered pairs of disjoint subsets of $S$ is equal to

In the following state whether $\mathrm{A = B}$ or not :

$A = \{ x:x$ is a multiple of $10\} ;B = \{ 10,15,20,25,30 \ldots  \ldots \} $

Which of the following are sets ? Justify your answer.

The collection of all boys in your class.

Write the following sets in the set-builder form :

${\rm{\{ 5,25,125,625\} }}$

Let $A=\{a, e, i, o, u\}$ and $B=\{a, b, c, d\} .$ Is $A$ a subset of $B ?$ No. (Why?). Is $B$ a subset of $A ?$ No. (Why?)

List all the elements of the following sers :

$B = \{ x:x$ is an integer $; - \frac{1}{2} < n < \frac{9}{2}\} $