950. Выполните действия:

a) $$4 \frac{3}{8} - (3 \frac{5}{7} - 1 \frac{5}{8}) + 1 \frac{5}{8} = 4 \frac{3}{8} - 3 \frac{5}{7} + 1 \frac{5}{8} + 1 \frac{5}{8} = (4 \frac{3}{8} + 1 \frac{5}{8} + 1 \frac{5}{8}) - 3 \frac{5}{7} = 7 \frac{3}{8} - 3 \frac{5}{7} = \frac{59}{8} - \frac{26}{7} = \frac{59 \times 7 - 26 \times 8}{56} = \frac{413 - 208}{56} = \frac{205}{56}$$
б) $$12 \frac{7}{12} - 4 \frac{5}{12} - (20 \frac{3}{4} - 19 \frac{3}{4}) = 12 \frac{7}{12} - 4 \frac{5}{12} - 1 = (12-4-1) + (\frac{7}{12} - \frac{5}{12}) = 7 + \frac{2}{12} = 7 \frac{1}{6}$$