Divide the sum of $\dfrac{13}{5} \text{ and } \dfrac{-12}{7}$ by the product of $\dfrac{-31}{7} \text{ and } \dfrac{1}{-2}$.

Divide the sum of $\dfrac{65}{12} \text{ and } \dfrac{8}{3}$ by their difference.

[Hint: Here we have to find $\left(\dfrac{65}{12} + \dfrac{8}{3}\right) \div \left(\dfrac{65}{12} - \dfrac{8}{3}\right)$]

Find the area of a rectangular part which is $36\dfrac{3}{5}$ m long and $16\dfrac{2}{5}$ m broad.

Find the area of a square plot of land whose each side measures $8\dfrac{1}{2}$ metres.

[Hint: Area of the plot = side² = $\left(8\dfrac{1}{2}\right)^2$ sq. m = $\left(8\dfrac{1}{2} \times 8\dfrac{1}{2}\right)$ sq. m]