1. Вычислите: а) 7/18 + 5/12; б) 6 3/8 − 2 11/24; в) 18/35 − 25/21; г) 2 2/5 : 1 1/6.

а) \(\frac{7}{18}+\frac{5}{12}=\frac{14}{36}+\frac{15}{36}=\frac{29}{36}\).

б) \(6\frac{3}{8}-2\frac{11}{24}=6\frac{9}{24}-2\frac{11}{24}=3\frac{22}{24}=3\frac{11}{12}\).

в) \(\frac{18}{35}-\frac{25}{21}=\frac{54}{105}-\frac{125}{105}=-\frac{71}{105}\).

г) \(2\frac{2}{5}:1\frac{1}{6}=\frac{12}{5}:\frac{7}{6}=\frac{12}{5}\cdot\frac{6}{7}=\frac{72}{35}=2\frac{2}{35}\).

Ответ: а) \(\frac{29}{36}\); б) \(3\frac{11}{12}\); в) \(-\frac{71}{105}\); г) \(2\frac{2}{35}\).