\documentclass{article}
\usepackage{amsmath} % pkg required by EasyLatex
\usepackage{amsfonts} % pkg required by EasyLatex
\usepackage{amssymb} % pkg required by EasyLatex
\usepackage{psfrag} % pkg required by EasyLatex
\usepackage[dvips]{graphicx} % pkg required by EasyLatex

\begin{document}



\begin{align*}
1 + 1 &= 2
\\1 &= 2 - 1
\\0 &= 2 - 1 - 1
\\0 &= 2 - 2
\end{align*}

\end{document}
