1. (10 points) $3 \frac{3}{4}+5 \frac{5}{6}+7 \frac{7}{8}=$ $\qquad$
【Analysis】Directly find a common denominator, and then add the fractions with the same denominator.
【Solution】Solution: $3 \frac{3}{4}+5 \frac{5}{6}+7 \frac{7}{8}$
$$
\begin{array}{l}
=3 \frac{18}{24}+5 \frac{20}{24}+7 \frac{21}{24} \\
=17 \frac{11}{24} .
\end{array}
$$

Therefore, the answer is: $17 \frac{11}{24}$.