\documentclass{minimal}
\usepackage{amsmath}
\usepackage[active,tightpage]{preview}
\setlength\PreviewBorder{1pt}
\usepackage{pgf}
\usepackage{tikz}
\usepgfmodule{plot}
\usepgflibrary{plothandlers}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{shadings}
\begin{document}
\begin{preview}
%tikz
\begin{tikzpicture}[every node/.style={draw,scale=1pt,
minimum width=20pt,inner sep=3pt,
line width=0pt,draw=black}]
\matrix[row sep=2pt,column sep=2pt]
{\node[fill=green]{86};&
\node[fill=blue]{87};&
\node[fill=green]{88};&
\node[fill=red]{89};\\
\node[fill=blue]{81};&
\node[fill=green]{82};&
\node[fill=red]{83};&
\node[left color=green,right color=blue]{84};&
\node[]{85};\\
};
\end{tikzpicture}
\end{preview}
\end{document}