答案1
以下是一种方法:
代码:
\documentclass{article}
\usepackage{tikz}
%% https://tex.stackexchange.com/a/100272/4301
\newcommand{\Cross}{%
\mathbin{%
\tikz [x=2.0ex,y=2.0ex,line width=.3ex, black] \draw (0,0) -- (1,1) (0,1) -- (1,0);
}%
}%
\begin{document}
\[
\begin{array}{r@{}c@{}l}
2y & & 3 \\
& {}\Cross{} & \\[-0.75ex]
3y & & 5 \\
\end{array}
\]
\end{document}