$\dfrac{1}{5} + \dfrac{7}{11} + \dfrac{5}{13} + 4 \times \left(\dfrac{1}{5} + \dfrac{1}{11}\right) + \dfrac{21}{13}$
$= \dfrac{1}{5} + \dfrac{7}{11} + \dfrac{5}{13} + \dfrac{4}{5} + \dfrac{4}{11} + \dfrac{21}{13}$
$= \left(\dfrac{1}{5} + \dfrac{4}{5}\right) + \left(\dfrac{5}{13} + \dfrac{21}{13}\right) + \left(\dfrac{7}{11}+\dfrac{4}{11}\right)$
$= 1 + 2 + 1$
$= 4$