\(\dfrac{5}{7}+\dfrac{4}{9}+\dfrac{15}{27}+\dfrac{2}{14}+\dfrac{1}{7}\)
\(=\left(\dfrac{5}{7}+\dfrac{2}{14}+\dfrac{1}{7}\right)+\left(\dfrac{4}{9}+\dfrac{15}{27}\right)\)
\(=\left(\dfrac{6}{7}+\dfrac{1}{7}\right)+\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)
=1+1
=2