TeX Quellcode:
\genfrac{}{}{1pt}{0}{-\frac{1}{9}}{\frac{1}{81}} = -\dfrac{1}{9} : \dfrac{1}{81} = -\dfrac{1}{9} \cdot \dfrac{81}{1} = -\dfrac{1}{1} \cdot \dfrac{9}{1} = -9