Ответ:
\(\frac{13}{24}-\frac{7}{12}-\frac{1}{6}=\frac{13-14-4}{24}=-\frac{5}{24}\).
\(21\cdot\left(-\frac{5}{24}\right)=-\frac{105}{24}=-\frac{35}{8}=-4\frac{3}{8}\).
Ответ: \(-4\frac{3}{8}\).
\(\frac{13}{24}-\frac{7}{12}-\frac{1}{6}=\frac{13-14-4}{24}=-\frac{5}{24}\).
\(21\cdot\left(-\frac{5}{24}\right)=-\frac{105}{24}=-\frac{35}{8}=-4\frac{3}{8}\).
Ответ: \(-4\frac{3}{8}\).