I need an equation in which the equation itself is centered and the equation number (a custom tag) is located more to the left.
\documentclass[a4paper,12pt,numbers=noenddot]{scrartcl}
\usepackage{mathtools}
\usepackage{amsmath}
\begin{document}
%here the equation number is at the far right
\begin{align}
\tag{\text{tag}}
2 + 2 = 4
\end{equation}
%and here the equation number is indented, but the equation itself is not centered
\begin{align*}
2 + 2 &= 4
&&\text{tag}
%and here a bracket remains on the right side
\begin{equation}
\tag{\text{tag}\qquad\quad}
2 + 2 = 4
\end{equation}
\end{document}
How can I fix this?
\begin{quote}\begin{equation}...\end{equation}\end{quote}
which (in most classes) will set the equation in a narrower text block/ – David Carlisle May 19 '20 at 10:08