12) 1 1/15 − 1 4/24

\(1\frac{1}{15}-1\frac{4}{24}=\frac{1}{15}-\frac{1}{6}=\frac{2}{30}-\frac{5}{30}=-\frac{3}{30}=-\frac{1}{10}\).

Ответ: −1/10