Ответ:

\(2\frac{1}{5}+3\frac{2}{5}=5\frac{3}{5}\).

\(7\frac{14}{15}-2\frac{4}{15}=5\frac{10}{15}=5\frac{2}{3}\).

\(10\frac{4}{7}-6\frac{1}{7}=4\frac{3}{7}\).

Ответ: \(5\frac{3}{5};\ 5\frac{2}{3};\ 4\frac{3}{7}\).