I wanted to compile this, but I had difficulty.

```
\begin{multicols}{2}
\begin{enumerate}
 \item\[\begin{array}{rl}
  & p\land q\\
  & p\\
  \arrayrulecolor{red}\cline{2-2}
  \therefore & q
  \end{array}\]
 \item\[\begin{array}{rl}
  & p\rightarrow q\\
  & q\rightarrow r\\
  \arrayrulecolor{red}\cline{2-2}
  \therefore & p\rightarrow r
  \end{array}\]
  \item\[\begin{array}{rl}
  & p\\
  \arrayrulecolor{red}\cline{2-2}
  \therefore & p\lor q
  \end{array}\] 
% \item\[\begin{array}{rl}
  %& p\lor q\\
  %& p\rightarrow r\\
 % & q\rightarrow s\\\arrayrulecolor{red}\cline{2-2}
 %\therefore & r\lor s
 % \end{array}/] 
 %\item[]Simplificaci\'on\\
 %\item[]Silogismo Hipot\'etico\\
 %\item[]Ley de adici\'on\\
% \item[]Silogismo Disyuntivo
 \end{enumerate}
 \end{multicols} 

```