\[Dings=DADA+n\]
Dings= "DADA"+n
danke für eure Hilfe

\[Dings=DADA+n\]

\documentclass[11pt,a4paper]{scrartcl}
\usepackage[latin1]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\begin{document}
\[Dings=\text{\textquotedbl}\!DADA\text{\textquotedbl}+n\] 
\end{document}
