3. Вычислите: a) $$4\frac{1}{6} \cdot (1\frac{1}{3} + 3\frac{5}{6}) \cdot 6$$; б) $$(6 - 2\frac{4}{5}) \cdot 3\frac{1}{8} - 1\frac{3}{4}$$

a) $$4\frac{1}{6} \cdot (1\frac{1}{3} + 3\frac{5}{6}) \cdot 6 = \frac{25}{6} \cdot (\frac{4}{3} + \frac{23}{6}) \cdot 6 = \frac{25}{6} \cdot (\frac{8}{6} + \frac{23}{6}) \cdot 6 = \frac{25}{6} \cdot \frac{31}{6} \cdot 6 = \frac{25 \cdot 31}{6} = \frac{775}{6} = 129\frac{1}{6}$$
б) $$(6 - 2\frac{4}{5}) \cdot 3\frac{1}{8} - 1\frac{3}{4} = (6 - \frac{14}{5}) \cdot \frac{25}{8} - \frac{7}{4} = (\frac{30}{5} - \frac{14}{5}) \cdot \frac{25}{8} - \frac{7}{4} = \frac{16}{5} \cdot \frac{25}{8} - \frac{7}{4} = \frac{2}{1} \cdot \frac{5}{1} - \frac{7}{4} = 10 - \frac{7}{4} = \frac{40}{4} - \frac{7}{4} = \frac{33}{4} = 8\frac{1}{4}$$
Ответ: a) $$129\frac{1}{6}$$; б) $$8\frac{1}{4}$$