### Exercise condition:

4
(Note: Submit the answer without simplifying the fraction.)

(i) $\left(\frac{12}{3}+\frac{-24}{3}\right)$ $$=$$ $\left(\frac{-24}{3}+\frac{12}{3}\right)$ $$=$$ $\frac{i}{i}$.

(ii) $\left(\frac{10}{4}×\frac{5}{2}\right)$$$=$$ $\left(\frac{5}{2}×\frac{10}{4}\right)$ $$=$$ $\frac{i}{i}$.