Вычислите: 1) \(\frac{7}{8}-\frac{5}{6}\); 2) \(\frac{7}{8}+\frac{3}{18}\); 3) \(\frac{10}{8}-1\); 4) \(\frac{5}{10}-2\cdot\frac{4}{10}\).

1. \(\frac{7}{8}-\frac{5}{6}=\frac{21}{24}-\frac{20}{24}=\frac{1}{24}\).
2. \(\frac{7}{8}+\frac{3}{18}=\frac{7}{8}+\frac{1}{6}=\frac{21}{24}+\frac{4}{24}=\frac{25}{24}=1\frac{1}{24}\).
3. \(\frac{10}{8}-1=\frac{10}{8}-\frac{8}{8}=\frac{2}{8}=\frac{1}{4}\).
4. \(\frac{5}{10}-2\cdot\frac{4}{10}=\frac{5}{10}-\frac{8}{10}=-\frac{3}{10}\).

Ответ: 1) \(\frac{1}{24}\); 2) \(1\frac{1}{24}\); 3) \(\frac{1}{4}\); 4) \(-\frac{3}{10}\).