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

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

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

$B^{\prime}$

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

$\{ x:x$ is a perfect square $\} $

If $U=\{a, b, c, d, e, f, g, h\},$ find the complements of the following sets:

$D=\{f, g, h, a\}$

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

$\{x: x+5=8\}$

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

$A^{\prime}$