If $A$ and $B$ be any two sets, then $(A \cap B)'$ is equal to

Taking the set of natural numbers as the universal set, write down the complements of the following sets:

$\{ x:x$ is an odd natural number $\} $

Taking the set of natural numbers as the universal set, write down the complements of the following sets:

$\{ x:x$ is a prime number $\} $

Fill in the blanks to make each of the following a true statement :

$A \cup A^{\prime}=\ldots$

Let $U=\{1,2,3,4,5,6,7,8,9,10\}$ and $A=\{1,3,5,7,9\} .$ Find $A^{\prime}$

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

$A^{\prime}$