1.8. Вычислите: \(\frac{1}{25}-\frac{7}{50}\).

\(\frac{1}{25}=\frac{2}{50}\).

\(\frac{2}{50}-\frac{7}{50}=-\frac{5}{50}=-\frac{1}{10}\).

Ответ: \(-\frac{1}{10}\).