\[\frac{2}{1 \cdot 3} + \frac{2}{3 \cdot 5} + \frac{2}{5 \cdot 7} + \ldots + \frac{2}{99 \cdot 101} =\]
\[= \left( \frac{1}{1} - \frac{1}{3} \right) + \left( \frac{1}{3} - \frac{1}{5} \right) + \left( \frac{1}{5} - \frac{1}{7} \right) + \ldots +\]
\[+ \left( \frac{1}{99} - \frac{1}{101} \right) =\]
\[= \frac{1}{1} - \frac{1}{3} + \frac{1}{3} - \frac{1}{5} + \frac{1}{5} - \frac{1}{7} + \ldots + \frac{1}{99} - \frac{1}{101} =\]
\[= \frac{1}{1} - \frac{1}{101} = \frac{101}{101} - \frac{1}{101} = \frac{100}{101}.\]
\[Ответ:\frac{100}{101}.\]