\[\boxed{\mathbf{109.}}\]
\[\textbf{а)}\ \frac{5}{6} \cdot \frac{4}{6} = \frac{5}{9}.\]
\[\textbf{б)}\ \frac{5}{6} \cdot \frac{4}{6} \cdot \frac{3}{6} = \frac{5}{9} \cdot \frac{1}{2} = \frac{5}{18}.\]
\[\textbf{в)}\ \frac{5}{18} \cdot \frac{2}{6} = \frac{5}{18} \cdot \frac{1}{3} = \frac{5}{54}.\]
\[\textbf{г)}\ \frac{5}{54} \cdot \frac{1}{6} = \frac{5}{324}.\]
\[\textbf{д)}\ \frac{5}{324} \cdot 0 = 0.\]