Question:
A drum full of rice weighs $40 \frac{1}{6} \mathrm{~kg}$. If the empty drum weighs $13 \frac{3}{4} \mathrm{~kg}$, find the weight of rice in the drum.
Solution:
Weight of rice in the drum = Weight of the drum full of rice - Weight of the empty drum
$=40 \frac{1}{6}-13 \frac{3}{4}$
$=\left(40+\frac{1}{6}\right)-\left(13+\frac{3}{4}\right)$
$=\frac{241}{6}-\frac{55}{4}$
$=\frac{241}{6}+\left(\right.$ Additive inverse of $\left.\frac{55}{4}\right)$
$=\frac{482-165}{12}$
$=\frac{317}{12}$
$=26 \frac{5}{12} \mathrm{~kg}$
Therefore, the weight of rice in the drum is $26 \frac{5}{12} \mathrm{~kg}$.