Beamer - stop page numbering

Question

I would like to stop the page numbering for some slides that are basically the same. Does anyone know how to do it?

I attach a (MWE) example below. As you can see in the first slide I highlight in red the title of column 1, in the second slide (identical to the previous one) I highlight column 2. Latex counts two slides, whereas I would like to count only the first.

\documentclass[10pt,notes=show,beamer]{beamer}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{amssymb}
\usepackage{mathpazo}
\usepackage{hyperref}
\usepackage{multimedia}
\usepackage{amsfonts}
\usepackage{amsmath}
\usepackage{graphicx}
\usepackage{epstopdf}
\usepackage{color}


\setcounter{MaxMatrixCols}{10}

%%%%%%%%%%% BEAMER TEMPLATE %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\mode<presentation>
{
    \usetheme[compress]{Singapore}
    \setbeamercovered{transparent}
}
\setbeamertemplate{footline}[frame number]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% END PREAMBLE
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}


\begin{frame}{First slide}

\begin{table}
    \begin{tabular}{ll}
        \textcolor{red}{Column 1} & Column 2  \\
        \hline \hline
        num1    & num2   \\
        \hline
    \end{tabular}
\end{table}

\end{frame}

\begin{frame}{Second slide}

\begin{table}
    \begin{tabular}{ll}
        Column 1 & \textcolor{red}{Column 2}  \\
        \hline \hline
        num1    & num2   \\
        \hline
    \end{tabular}
\end{table}

\end{frame}

\end{document}

Answer 1

The solution is the command \alert:

\documentclass{beamer}
\mode<presentation>
{
    \usetheme[compress]{Singapore}
    \setbeamercovered{transparent}
}
\setbeamertemplate{footline}[frame number]
\begin{document}

\begin{frame}{First slide}

    \begin{table}
        \begin{tabular}{ll}
            \alert<1>{Column 1} & \alert<2>{Column 2}\\
            \hline \hline
            num1    & num2   \\
            \hline
        \end{tabular}
    \end{table}

\end{frame}
\end{document}

Answer 2

Do you know the commands \only and \visible added by beamer? Those might help you. If you really want to use two frame environments, you could decrease the counter by 1 or use the handy option noframenumbering (the latter might be preferred as it's the way beamer wants you to do it). The following uses both approaches:

\documentclass[10pt,notes=show,beamer]{beamer}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\usepackage{hyperref}
\usepackage{color}


%%%%%%%%%%% BEAMER TEMPLATE %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\mode<presentation>
{
    \usetheme[compress]{Singapore}
    \setbeamercovered{transparent}
}
\setbeamertemplate{footline}[frame number]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% END PREAMBLE
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}


\begin{frame}{First slide}

\begin{table}
    \begin{tabular}{ll}
        \textcolor{red}{Column 1} & Column 2  \\
        \hline \hline
        num1    & num2   \\
        \hline
    \end{tabular}
\end{table}

\end{frame}

%\addtocounter{framenumber}{-1}% possible alternative

\begin{frame}[noframenumbering]{Second slide}

\begin{table}
    \begin{tabular}{ll}
        Column 1 & \textcolor{red}{Column 2}  \\
        \hline \hline
        num1    & num2   \\
        \hline
    \end{tabular}
\end{table}

\end{frame}

\begin{frame}{combined}% >>>
  \begin{table}
    \begin{tabular}{ll}
      \only<1>{\textcolor{red}}{Column 1}
        & \only<2>{\textcolor{red}}{Column 2}\\
      \hline\hline
      num1 & num2 \\
      \hline
    \end{tabular}
  \end{table}
\end{frame}% <<<


\end{document}

As @samcarter pointed out, beamer alters the command \textcolor to also support \textcolor<1>{red}{Column 1} and \textcolor<2>{red}{Column 2}. So instead of \only<1>{\textcolor{red}}{Column 1} one could also use that.