2. (5 points) $15+115+1115+11115+\cdots+1111111115=$
【Solution】Solution: $15+115+1115+11115+11115+\cdots+1111111115$,
$$
\begin{array}{l}
=(10+110+1110+11110+1111110+1111110+11111110+111111110+1111111110)+5 \times 9, \\
=1234567890+45, \\
=1234567935 .
\end{array}
$$

The answer is: 1234567935 .