答案1
像这样:
使用包enumerate
列表enumitem
:
\documentclass{article}
\usepackage{enumitem}
\begin{document}
\begin{enumerate}[label=\alph{*}), align=left, leftmargin=*]
\item $D = (B - A) \cup (A - (B \cup C)) \cup (C - A)$
\item $A = \{1,2,3,4,5,6,7\}$
\item $B = \{2,5,6,9,10\}$
\item $C = \{4,7,8,11,12\}$
\item $A = \{1,2,8\}$
\item $B = \{6,7\}$
\item $C = \{2,3,4,5,7\}$
\end{enumerate}
\end{document}