\[\frac{5}{7} + \frac{5}{9} + \frac{2}{7} + \frac{4}{9} = \frac{7}{7} + \frac{9}{9} =\]
\[= \left( \frac{5}{7} + \frac{2}{7} \right) + \left( \frac{5}{9} + \frac{4}{9} \right) = 1 + 1 =\]
\[= 2\]