Answer
$\dfrac{0}{4} = 0$ because $4(0) = 0$
$\dfrac{4}{0}$ is undefined because there is no real number that when multiplied by $0$ will give 4 as the product.
Work Step by Step
RECALL:
If $\dfrac{a}{b} = c $, then $a = bc$
Thus,
(i) $\dfrac{0}{4} = 0$ because $4(0) = 0$
(ii) $\dfrac{4}{0}$ is undefined because there is no real number that when multiplied by $0$ will give 4 as the product.
