Consider the following MWE:
Code: Select all
\documentclass{article}
\usepackage{mathtools}
\newcommand{\cm}{\,\textup{cm}}
\begin{document}
\begin{align}
O &= 8 \cdot (50 \pm 0{,}5)\cm = (400 \pm 4{,}0)\cm,\\
h &= (3 \cdot 178 + 6 \pm 10)\cm = (540 \pm 10)\cm.
\end{align}
\end{document}

Thank you in advance!