Ответ:

а) \(\frac{7}{12}-\frac{5}{12}=\frac{2}{12}=\frac{1}{6}\).

б) \(\frac{9}{10}+\frac{3}{10}=\frac{12}{10}=1\frac{1}{5}\).

в) \(\frac{1}{18}+\frac{11}{18}=\frac{12}{18}=\frac{2}{3}\).

г) \(\frac{11}{15}-\frac{2}{15}=\frac{9}{15}=\frac{3}{5}\).

Ответ: а) \(\frac{1}{6}\); б) \(1\frac{1}{5}\); в) \(\frac{2}{3}\); г) \(\frac{3}{5}\).