1. Вычислите: а) 7/15 + 5/12; б) 6 5/8 − 2 11/16; в) 18/35 · 25/27; г) 2 2/5 : 1 1/6.

а) \(\frac{7}{15}+\frac{5}{12}=\frac{28}{60}+\frac{25}{60}=\frac{53}{60}\).

б) \(6\frac{5}{8}=6\frac{10}{16}=5\frac{26}{16}\).

\(5\frac{26}{16}-2\frac{11}{16}=3\frac{15}{16}\).

в) \(\frac{18}{35}\cdot\frac{25}{27}=\frac{2}{7}\cdot\frac{5}{3}=\frac{10}{21}\).

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) \(\frac{53}{60}\); б) \(3\frac{15}{16}\); в) \(\frac{10}{21}\); г) \(2\frac{2}{35}\).