\[0,2555\ldots\]
\[0,2555 = 0,2 + 0,05 + 0,005 + \ldots\]
\[b_{1} = 0,05;\ \ \ \ \]
\[q = 0,1;\]
\[S = \frac{0,05}{1 - 0,1} = \frac{0,05}{0,9} = \frac{5}{90} = \frac{1}{18}\]
\[0,2 + \frac{1}{18} = \frac{2}{10} + \frac{1}{18} = \frac{23}{90}.\]
\[0,2555\ldots = \frac{23}{90}\]