(i) What number should be added to $\dfrac{5}{12}$ to get $2\dfrac{3}{8}$?

(ii) What number should be subtracted from 5 to get $1\dfrac{5}{13}$?

(i) Required number = $2\dfrac{3}{8} - \dfrac{5}{12}$

LCM of 8 and 12 = 24.

$\Rightarrow \dfrac{19}{8} - \dfrac{5}{12}\\[1em] \Rightarrow \dfrac{19 \times 3}{8 \times 3} - \dfrac{5 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{57}{24} - \dfrac{10}{24}\\[1em] \Rightarrow \dfrac{57 - 10}{24}\\[1em] \Rightarrow \dfrac{47}{24}\\[1em] \Rightarrow 1\dfrac{23}{24}$

Hence, the required number = $1\dfrac{23}{24}$.

(ii) Required number = $5 - 1\dfrac{5}{13}$

$\Rightarrow \dfrac{5}{1} - \dfrac{18}{13}\\[1em] \Rightarrow \dfrac{5 \times 13}{1 \times 13} - \dfrac{18}{13}\\[1em] \Rightarrow \dfrac{65}{13} - \dfrac{18}{13}\\[1em] \Rightarrow \dfrac{65 - 18}{13}\\[1em] \Rightarrow \dfrac{47}{13}\\[1em] \Rightarrow 3\dfrac{8}{13}$

Hence, the required number = $3\dfrac{8}{13}$.