\[5\frac{3}{7} + \left( - 3\frac{5}{28} \right) - \left( - 1\frac{9}{14} \right) =\]
\[= 5\frac{12}{28} - 3\frac{5}{28} + 1\frac{18}{28} =\]
\[= 2\frac{7}{28} + 1\frac{18}{28} = 3\frac{25}{28}\]