答案1
我不清楚单元格内容应该居中还是左对齐。以下解决方案假设它们应该左对齐。
\documentclass{article}
\usepackage{array} % for 'w' column type
\begin{document}
\sffamily % optional
\setlength\extrarowheight{3pt} % optional (for a more open "look")
\begin{tabular}{|*{3}{wl{7mm}|}} % use 'wc' rather than 'wl' if centering is desired
\cline{1-1}
0.1 \\
\hline
0.2 & 0.4 & 0.5\\
\hline
0.3 \\
\cline{1-1}
\end{tabular}
\end{document}