7. \(\frac{2}{3}-\frac{2}{5}=\)

Общий знаменатель — 15: \(\frac{2}{3}=\frac{10}{15}\), \(\frac{2}{5}=\frac{6}{15}\).

\(\frac{10}{15}-\frac{6}{15}=\frac{4}{15}\).

Ответ: \(\frac{4}{15}\).