7. Вычисли: a) $$15\frac{3}{4} - (8\frac{1}{4} - 4\frac{2}{4} + 2)$$ б) $$(3\frac{3}{14} + 1\frac{11}{14}) + 7\frac{13}{14} * (5\frac{5}{14} - 2\frac{6}{14})$$

a) $$15\frac{3}{4} - (8\frac{1}{4} - 4\frac{2}{4} + 2) = 15\frac{3}{4} - (8\frac{1}{4} - 4\frac{1}{2} + 2) = 15\frac{3}{4} - (3\frac{3}{4} + 2) = 15\frac{3}{4} - 5\frac{3}{4} = 10$$ б) $$(3\frac{3}{14} + 1\frac{11}{14}) + 7\frac{13}{14} * (5\frac{5}{14} - 2\frac{6}{14}) = (4\frac{14}{14}) + 7\frac{13}{14} * (2\frac{-1}{14}) = 5 + 7\frac{13}{14} * (1\frac{13}{14}) = 5 + \frac{10\frac{13}{14}}{1} * \frac{27}{14} = 5 + \frac{111}{14} * \frac{27}{14} = 5 + \frac{3097}{196} = 5 + 15\frac{167}{196} = 20\frac{167}{196}$$