The number of proper subsets of the set $\{1, 2, 3\}$ is

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 a universal set for all the three sets $A$,$B$ and $C$?

Let $A = \{1, 2, 3, 4, 5, 6\}$. Insert the appropriate symbol $\in$ or $\notin$ in the blank space:
$0 \dots A$

State which of the following sets are finite or infinite:
$\{ x : x \in N \text{ and } x \text{ is odd} \}$

If $A = \{1, 2, 3, 4, 5, 6\}$, then which of the following statements is not true?

Determine whether the following set is finite or infinite:
$\{1, 2, 3, \ldots, 99, 100\}$