documentclass[11pt]{beamer}
usepackage{beamerthemesplit}
usetheme{Copenhagen}
usepackage{ragged2e}
setbeamercovered{transparent}
newcommand*oldmacro{}%
letoldmacroinsertshorttitle%
renewcommand*insertshorttitle{%
oldmacrohfill%
insertframenumber,/,inserttotalframenumber}
letolditem=item%
renewcommand{item}{olditem justifying}
makeatletter
renewcommand{maketag@@@}[1]{hbox{m@thnormalsizenormalfont#1}}%
makeatother
begin{document}
section{Bla bla bla}
begin{frame}
begin{itemize}
item bla bla bla
begin{center}
centering
  begin{tabular}{|c|c|}
   hline
   1 & 2 \
   hline
   a & b \
   c & d \
   hline
 end{tabular}
end{center}
end{itemize}
end{frame}
end{document}