\[\boxed{\mathbf{324}\mathbf{.}}\]
\[1)\ \frac{6}{15} = \frac{2}{5}\]
\[2)\ \frac{14}{49} = \frac{2}{7}\]
\[3)\ \frac{10}{90} = \frac{1}{9}\]
\[4)\ \frac{44}{55} = \frac{4}{5}\]
\[5)\ \frac{25}{65} = \frac{5}{13}\]
\[6)\ \frac{18}{69} = \frac{6}{23}\]