$\frac{\frac{3}{4} - \frac{7}{12}}{\frac{3}{5} - \frac{3}{10}} + \frac{\frac{9}{10} - \frac{7}{8}}{\frac{7}{8} - \frac{5}{6}} + \frac{2 + 2\frac{2}{5}}{\frac{3}{4} + \frac{3}{7}} = \frac{\frac{3 * 3 - 7}{12}}{\frac{3 * 2 - 3}{10}} + \frac{\frac{9 * 4 - 7 * 5}{40}}{\frac{7 * 3 - 5 * 4}{24}} + \frac{4\frac{2}{5}}{\frac{3 * 7 + 3 * 4}{28}} = \frac{\frac{1}{6}}{\frac{3}{10}} + \frac{\frac{1}{40}}{\frac{1}{24}} + \frac{\frac{22}{5}}{\frac{33}{28}} = \frac{1}{6} * \frac{10}{3} + \frac{1}{40} * \frac{24}{1} + \frac{22}{5} * \frac{28}{33} = \frac{1}{2 * 3} * \frac{2 * 5}{3} + \frac{1}{8 * 5} * \frac{8 * 3}{1} + \frac{2 * 11}{5} * \frac{28}{3 * 11} = \frac{5}{9} + \frac{3}{5} + \frac{56}{15} = \frac{5 * 5 + 3 * 9 + 56 * 3}{45} = \frac{25 + 27 + 168}{45} = \frac{220}{45} = 4\frac{8}{9}$