If $A$ and $B$ are disjoint,then $n(A \cup B)$ is equal to

Let $V = \{a, e, i, o, u\}$ and $B = \{a, i, k, u\}$. Find $V - B$ and $B - V$.

If $A=\{3, 5, 7, 9, 11\}$,$B=\{7, 9, 11, 13\}$,$C=\{11, 13, 15\}$,and $D=\{15, 17\}$; find $(A \cup D) \cap (B \cup C)$.

If $A = \{ x : x \text{ is a natural number} \}$,$B = \{ x : x \text{ is an even natural number} \}$,$C = \{ x : x \text{ is an odd natural number} \}$,and $D = \{ x : x \text{ is a prime number} \}$,find $A \cap C$.

State whether the following statement is true or false. Justify your answer.
${2, 3, 4, 5}$ and ${3, 6}$ are disjoint sets.

If $A, B, C$ are three sets,then $A \cap (B \cup C)$ is equal to