6. \(9\frac{3}{15}-5\frac{9}{15}\)

\[9\frac{3}{15}-5\frac{9}{15}=8\frac{18}{15}-5\frac{9}{15}=3\frac{9}{15}=3\frac{3}{5}.\]

Ответ: \(3\frac{3}{5}\).