Fill in the blank to make the following statement true: $\varnothing^{\prime} \cap A = \text{?}$

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

$A$ and $B$ are events such that $P(A)=0.42$,$P(B)=0.48$ and $P(A \cap B)=0.16$. Determine $P(\text{not } A)$.

$A$ and $B$ are events such that $P(A)=0.42$,$P(B)=0.48$ and $P(A \cap B)=0.16$. Determine $P(\text{not } B)$.

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x: x \ge 7 \}$

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x : x \text{ is an odd natural number} \}$