2. (3 points) Calculate: $\frac{251}{2008 \times 2009}+\frac{251}{2009 \times 2010}=$ $\qquad$ .
【Solution】Solution: $\frac{251}{2008 \times 2009}+\frac{251}{2009 \times 2010}$,
$$
\begin{array}{l}
=251 \times\left(\frac{1}{2008 \times 2009}+\frac{1}{2009 \times 2010}\right), \\
=251 \times\left(\frac{1}{2008}-\frac{1}{2009}+\frac{1}{2009}-\frac{1}{2010}\right), \\
=251 \times \frac{2}{2008 \times 2010}, \\
=\frac{1}{8040}
\end{array}
$$

Therefore, the answer is: $\frac{1}{8040}$.