\newcommand*\rfrac[2]{{}^{#1}\!/_{#2}}
\begin{deloppgaver}

  \delo
    \[ -135\degree \cdot \frac{\pi}{180\degree} \approx -2.35  \]

  \delo
    \[ 1,5\pi \cdot \frac{180\degree}{\pi} = 270\deg  \]

  \delo
    \[ sin\left( \frac{-\pi}{2} \right) = -1\]

\end{deloppgaver}