答案1
\documentclass{article}
\usepackage{amsmath}
\newcommand\zfrac[2]{{\tabcolsep=2pt\begin{array}{c}%
#1\\
\noalign{\vskip-7pt}
\multicolumn{1}{@{}c@{}}{\rule[-3pt]{.4pt}{3pt}\hrulefill\rule{.4pt}{3pt}}\\
\noalign{\vskip-2pt}
#2\end{array}}}
\begin{document}
\[
\frac{1}{2} + \zfrac{1}{2} + \zfrac{111}{222}
\]
\end{document}