Выполните действия: 20: (6 1/14 + 1 11/14) – (4 1/4 – 2 3/4)

$$6 \frac{1}{14} + 1 \frac{11}{14} = 6 + \frac{1}{14} + 1 + \frac{11}{14} = 7 + \frac{1+11}{14} = 7 + \frac{12}{14} = 7 \frac{6}{7}$$ $$4 \frac{1}{4} - 2 \frac{3}{4} = 4 + \frac{1}{4} - 2 - \frac{3}{4} = 1 \frac{2}{4} = 1 \frac{1}{2}$$ $$20 : (7 \frac{6}{7} - 1 \frac{1}{2}) = 20 : (\frac{55}{7} - \frac{3}{2}) = 20 : (\frac{110 - 21}{14}) = 20 : \frac{89}{14} = 20 \cdot \frac{14}{89} = \frac{280}{89} = 3 \frac{13}{89}$$