If $U=\{a, b, c, d, e, f, g, h\},$ find the complements of the following sets:
$B=\{d, e, f, g\}$
Fill in the blanks to make each of the following a true statement :
$\varnothing^ {\prime}\cap A$
Taking the set of natural numbers as the universal set, write down the complements of the following sets:
$\{ x:x$ is a positive multiple of $3\} $
Taking the set of natural numbers as the universal set, write down the complements of the following sets:
$\{x: x+5=8\}$
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 $\} $