[most frequently used]
\pi
\frac {\empty }{\empty }[6_01.gif]
\root {}{\empty }[6_04.gif]
\empty ^{\empty }[5_01.gif]
\log{\empty}{\empty}[10_07.gif]
\bracem{()}{\empty}[10_01.gif]#;\: \empty
\emptyset#noSolution