An enumeration of equations with aligned equal signs
\documentclass[leqno]{report}
\usepackage{amsmath}
\begin{document}
\begin{flalign}
1 + 1 &= 2 &\\
1 &= 2 - 1
\end{flalign}
\end{document}
You could use \hphantom
for taking the required space for alignment:
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{enumerate}
\item $1 + 1 = 2$
\item $\hphantom{1+1}\mathllap{1} = 2 - 1$
\end{enumerate}
\end{document}
\usepackage{array}
\newenvironment{enumalign}
{\par\addvspace{\topsep}\setcounter{enumi}{0}
\noindent$\begin{array}{@{}r@{\hspace{\labelsep}}r@{}>{{}}l@{}}}
{\end{array}$\par\addvspace{\topsep}}
\newcommand{\eitem}{\stepcounter{enumi}\makebox[\labelwidth][r]{\theenumi.}&}
\begin{document}
\begin{enumalign}
\eitem 1+1&=2\\
\eitem 1&=2-1
\end{enumalign}
Remember to end the rows with \\