Let $U=\{1, 2, 3, 4, 5, 6, 7, 8, 9\}$,$A=\{1, 2, 3, 4\}$,$B=\{2, 4, 6, 8\}$,and $C=\{3, 4, 5, 6\}$. Find $(A \cup B)'$.

For the two events $A$ and $B$,$P(A) = 0.38$ and $P(B) = 0.41$. Find the value of $P(\text{not } A)$.

Two dice are thrown. The events $A, B$ and $C$ are as follows:
$A:$ getting an even number on the first die.
$B:$ getting an odd number on the first die.
$C:$ getting the sum of the numbers on the dice $\leq 5$.
Describe the event $\text{not } B$.

If $U = \{a, b, c, d, e, f, g, h\}$,find the complement of the set $D = \{f, g, h, a\}$.

Taking the set of natural numbers as the universal set,write down the complements of the following sets:
$A = \{ x : x \text{ is a perfect cube} \}$

If $U = \{a, b, c, d, e, f, g, h\}$,find the complement of the set $A = \{a, b, c\}$.