在数组环境中将文本与显示样式分数条垂直对齐

Question

我正在使用环境排版练习的子部分array。但是，练习编号的垂直中心与显示样式分数条不对齐（见下图）。array欢迎不使用其他方法，但请注意，不同行之间的垂直空间可以更改（例如\renewcommand{\arraystretch}{0.5}在我的代码中）。如果能帮助解决这种情况，我将不胜感激。

\documentclass[a5paper,12pt]{book}
\usepackage[top=1.5cm,bottom=2cm,includehead=true,inner=2cm,outer=1.8cm]{geometry}
\usepackage{amsmath,amsthm,amssymb}
\usepackage{array}


\begin{document}

\chapter{Chap}

\section{Sec}

text text text text text text text text text text text text text text text text text text text text text text text text text 

\subsection{Exercise}

\begin{equation*}
\renewcommand{\arraystretch}{0.5}
\begin{array}{r@{\enspace } >{$\displaystyle}m{4.4cm}<{$} r@{\enspace } >{$\displaystyle}m{4.4cm}<{$}}
1.  & {\frac{1}{2}}+{\frac{1}{5}}=       & 2.   & {\frac{3}{4}}+{\frac{5}{8}}=              \\
    &                                    &      &                                           \\
3.  & {\frac{7}{9}}+{\frac{16}{21}}=     & 4.   & {\frac{5}{6}}+{\frac{11}{14}}=            \\
    &                                    &      &                                           \\
5.  & {\frac{15}{22}}+{\frac{11}{26}}=   & 6.   & {\frac{103}{10}}+8{\frac{5}{16}}=         \\
\end{array}
\end{equation*}

\end{document}

Answer 1

为什么不追求简单呢？

\documentclass[a4paper,12pt]{book}
\usepackage{amsmath}
\usepackage{array}

\begin{document}

\chapter{Chap}

\section{Sec}

Some text for the section.
Some text for the section.
Some text for the section.
Some text for the section.
Some text for the section.

\subsection{Exercises}

\begingroup
\renewcommand{\arraystretch}{2.5}
\setlength{\arraycolsep}{0.5em}
\begin{tabular}{
  @{}
  l
  >{$\displaystyle}l<{$}
  @{\hspace{4em}}
  r
  >{$\displaystyle}l<{$}
  @{}
}
1.  & {\frac{1}{2}}+{\frac{1}{5}}=       & 2.   & {\frac{3}{4}}+{\frac{5}{8}}=              \\
3.  & {\frac{7}{9}}+{\frac{16}{21}}=     & 4.   & {\frac{5}{6}}+{\frac{11}{14}}=            \\
5.  & {\frac{15}{22}}+{\frac{11}{26}}=   & 6.   & {\frac{103}{10}}+8{\frac{5}{16}}=         \\
\end{tabular}
\endgroup

\end{document}

Answer 2

无论如何，练习数字都是在基线上输入的，而分数条则在数学轴上。

如果您确实想对齐它们，这里有一种方法，使用基于tasks包的更简单的代码：

\documentclass[a5paper,12pt]{book}
\usepackage[top=1.5cm,bottom=2cm,includehead=true,inner=2cm,outer=1.8cm]{geometry}
\usepackage{amsmath,amsthm,amssymb}
\usepackage{tasks}

\begin{document}

\chapter{Chap}

\section{Sec}

text text text text text text text text text text text text text text text text text text text text text text text text text

\subsection{Exercise}

\begin{tasks}[label=\raisebox{0.5ex}{\arabic*.} ](2)
\task $\dfrac{1}{2}+\dfrac{1}{5}= $
\task $ \dfrac{3}{4}+\dfrac{5}{8}= $
\task $ \dfrac{7}{9} + \dfrac{16}{21} = $
\task $ \dfrac{5}{6} + \dfrac{11}{14} = $
\task $ \dfrac{15}{22} + \dfrac{11}{26}= $
\task $ \dfrac{103}{10}+8\,\dfrac{5}{16} = $
\end{tasks}

\end{document}