4) 3\(\frac{3}{5}\) \(\cdot\) \(\frac{3}{7}\);

4) 3\(\frac{3}{5}\) \(\cdot\) \(\frac{3}{7}\) = \(\frac{3 \cdot 5 + 3}{5}\) \(\cdot\) \(\frac{3}{7}\) = \(\frac{18}{5}\) \(\cdot\) \(\frac{3}{7}\) = \(\frac{18 \cdot 3}{5 \cdot 7}\) = \(\frac{54}{35}\) = 1\(\frac{19}{35}\).

Ответ: 1\(\frac{19}{35}\)