Ответ:
а)
\(3\frac{7}{30}=\frac{97}{30}\), \(1\frac{5}{12}=\frac{17}{12}\), \(18\frac{1}{6}=\frac{109}{6}\).
\(\frac{97}{30}-\frac{17}{12}=\frac{194-85}{60}=\frac{109}{60}\).
\(\frac{109}{60}:\frac{109}{6}=\frac{109}{60}\cdot\frac{6}{109}=\frac{1}{10}\).
б)
\(1\frac{1}{2}+2\frac{2}{3}=\frac{3}{2}+\frac{8}{3}=\frac{25}{6}\).
\(\frac{25}{6}:1\frac{2}{3}=\frac{25}{6}:\frac{5}{3}=\frac{25}{6}\cdot\frac{3}{5}=\frac{5}{2}=2\frac{1}{2}\).
в)
\(1\frac{7}{12}=\frac{19}{12}\), поэтому \(\frac{11}{18}-\frac{19}{12}=\frac{22-57}{36}=-\frac{35}{36}\).
\(2\frac{1}{6}+\frac{7}{30}=\frac{13}{6}+\frac{7}{30}=\frac{65+7}{30}=\frac{12}{5}\).
\(-\frac{35}{36}\cdot\frac{12}{5}=-\frac{7}{3}=-2\frac{1}{3}\).
г)
\(3\frac{2}{5}-5=\frac{17}{5}-5=-\frac{8}{5}\).
\(\frac{31}{48}+\frac{7}{24}=\frac{31}{48}+\frac{14}{48}=\frac{45}{48}=\frac{15}{16}\).
\(-\frac{8}{5}\cdot\frac{15}{16}=-\frac{3}{2}=-1\frac{1}{2}\).
Ответ: а) \(\frac{1}{10}\); б) \(2\frac{1}{2}\); в) \(-2\frac{1}{3}\); г) \(-1\frac{1}{2}\).
