24. Найдите значение выражения: 1) −4/9 − 5/18; 2) 3/8 − 5/12; 3) −11/12 − (−9/10); 4) −8/15 − 13/20.

1. \( -\frac{4}{9}-\frac{5}{18}=-\frac{8}{18}-\frac{5}{18}=-\frac{13}{18} \).
2. \( \frac{3}{8}-\frac{5}{12}=\frac{9}{24}-\frac{10}{24}=-\frac{1}{24} \).
3. \( -\frac{11}{12}-\left(-\frac{9}{10}\right)=-\frac{11}{12}+\frac{9}{10}=\frac{-55+54}{60}=-\frac{1}{60} \).
4. \( -\frac{8}{15}-\frac{13}{20}=-\frac{32}{60}-\frac{39}{60}=-\frac{71}{60}=-1\frac{11}{60} \).

Ответ: 1) \(-\frac{13}{18}\); 2) \(-\frac{1}{24}\); 3) \(-\frac{1}{60}\); 4) \(-1\frac{11}{60}\).