1. Given $\frac{2+4+6+8}{1+3+5+7}-\frac{1+3+5+7}{2+4+6+8}=\frac{m}{n}$, where $\mathbf{m}, \mathbf{n}$ are two coprime positive integers, then $10 m+n=$ $\qquad$
【Answer】110
Analysis: Original expression $=\frac{20}{16}-\frac{16}{20}=\frac{9}{20}, 10 m+n=10 \times 9+20=110$