If $A$ and $B$ are two sets,then $A \cap (B - A)$ is equal to:

Find the union of each of the following pairs of sets:
$A = \{ x : x \text{ is a natural number and a multiple of } 3 \}$
$B = \{ x : x \text{ is a natural number less than } 6 \}$

Which of the following pairs of sets are disjoint?
${1, 2, 3, 4}$ and ${x : x \text{ is a natural number and } 4 \le x \le 6}$

If $A = \{1, 2, 3\}$ and $B = \{3, 8\}$,then find $(A \cup B) \times (A \cap B)$.

The simplified switching circuit for the following circuit is

State whether the following statement is true or false. Justify your answer.
${a, e, i, o, u}$ and ${a, b, c, d}$ are disjoint sets.