\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\usepackage{color}
\pagestyle{empty}
\begin{document}
\begin{equation*}
  \aligned 
    a &= 3.2, \quad& b &= 0.6, \quad& c &= 50, \\
    d &= 0.56, \quad& k &= 125 \quad& r &= 1.6.
  \endaligned
\end{equation*}
\end{document}