文本上方和下方的水平线

Question

我怎样才能在环境中有两条线 - 一条在文本（或数字）的上方，一条在下方align。就像儿童数学题中的和一样。在给定的示例中，我需要在最后一行的 26 上方和下方各有一条线，而不会对行距产生很大影响。我更喜欢不用表格。

 \textbf{Amy has 12 red buttons and 14 green buttons. How many buttons does she have in all?} \par
\vspace{5mm}
\begin{align*}
&\text{Number of red buttons} & & 12\\
&\text{Number of green buttons} & &14\\
&\text{Total number of buttons Amy has} & &26\\
\end{align*}

Answer 1

tabular您可以在顶部和底部设置答案\hline。为了确保它不影响行距，\smash它：

\documentclass{article}

\usepackage{amsmath}

\newcommand{\Answer}[1]{\smash{\begin{tabular}{l} \hline #1 \\ \hline \end{tabular}\hspace*{-\tabcolsep}}}

\begin{document}

\noindent
Amy has 12 red buttons and 14 green buttons. How many buttons does she have in all?
\begin{align*}
  & \text{Number of red buttons}           & 12 \\
  & \text{Number of green buttons}         & 14 \\
  & \text{Total number of buttons Amy has} & \Answer{26}
\end{align*}

\noindent
Amy has 12 red buttons and 14 green buttons. How many buttons does she have in all?
\begin{center}
  \begin{tabular}{ l @{\qquad} r }
    Number of red buttons           & 12 \\
    Number of green buttons         & 14 \\
    Total number of buttons Amy has & \Answer{26}
  \end{tabular}
\end{center}

\end{document}

您也可以在中设置内容tabular，并调整垂直填充如果需要的话，与 相匹配align。

Answer 2

另一个简单的解决方案：

 \documentclass{article}

\usepackage{amsmath}

\begin{document}

Amy has 12 red buttons and 14 green buttons. How many buttons does she have in all?
\begin{align*}
  & \text{Number of red buttons} & 12 \\
  & \text{Number of green buttons} & 14 \\
  & \text{Total number of buttons Amy has} & \smash{\overline{\underline{26\mathstrut}}}
\end{align*}

\end{document}