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 \textheight15cm \textwidth7cm \parindent0mm \parskip 1ex plus2ex minus0.8ex
\begin{document}
\section*{6.  Variable-sized Symbols:}

\begin{multicols}{2}
$\sum      $ \verb|:\sum|\\ 
$\int      $ \verb|:\int|\\ 
$\oint     $ \verb|:\oint|\\ 
$\prod     $ \verb|:\prod|\\ 
$\coprod   $ \verb|:\coprod|\\ 
$\bigcap   $ \verb|:\bigcap|\\ 
$\bigcup   $ \verb|:\bigcup|\\ 
$\bigsqcup $ \verb|:\bigsqcup|\\ 
$\bigvee   $ \verb|:\bigvee|\\ 
$\bigwedge $ \verb|:\bigwedge|\\ 
$\bigodot  $ \verb|:\bigodot|\\ 
$\bigotimes$ \verb|:\bigotimes|\\ 
$\bigoplus $ \verb|:\bigoplus|\\ 
$\biguplus $ \verb|:\biguplus|
\end{multicols}

\end{document}
