[OS X TeX] Multicolumn lists

[John B. Thoo]

Hello, everyone.  I apologize that this is not strictly a Mac TeX  
question.  If this is inappropriate, please delete it; however, I  
would appreciate any help.

My question is this: How can I create a multicolumn list with the  
item numbers aligned horizontally?  This doesn't work:

\usepackage[]{multicol}
...

\begin{enumerate} \itemsep 2ex
\begin{multicols}{2}
   \item  $x + \dfrac{1}{8} x = 12$
   \item  $x + \dfrac{1}{4} x + \dfrac{1}{6} x = 12$
   \item  $3(x - 1) - x = 7$
   \item  $4 \biggl( \dfrac{1}{2} x + 1 \biggr) - 3x = 12$
\end{multicols}
\end{enumerate}

Thanks.

---John.