Вычислите: 1) 2/3 + 3/5; 2) 7/8 − 9/16; 3) 16/35 − 3/10; 4) 4/15 + 2/9.

1. Приводим дроби к общему знаменателю: \(\frac{2}{3}+\frac{3}{5}=\frac{10}{15}+\frac{9}{15}=\frac{19}{15}=1\frac{4}{15}\).

2. \(\frac{7}{8}-\frac{9}{16}=\frac{14}{16}-\frac{9}{16}=\frac{5}{16}\).

3. \(\frac{16}{35}-\frac{3}{10}=\frac{32}{70}-\frac{21}{70}=\frac{11}{70}\).

4. \(\frac{4}{15}+\frac{2}{9}=\frac{12}{45}+\frac{10}{45}=\frac{22}{45}\).

Ответ: 1) \(1\frac{4}{15}\); 2) \(\frac{5}{16}\); 3) \(\frac{11}{70}\); 4) \(\frac{22}{45}\).