% Driver file for adding page numbers to slides prior to creating handout
\documentclass{article}
\usepackage{pdfpages}
\usepackage{fancyhdr}
\usepackage[a4paper,landscape, pdftex,vmargin=25mm,hmargin=12mm]{geometry}

\cfoot{}
\rfoot{\LARGE\sffamily\thepage}
\renewcommand{\headrule}{}

\begin{document}
\includepdf[pages=1]{slides.pdf}
\includepdf[pages=2-,pagecommand={\thispagestyle{fancy}}]{slides.pdf}
\end{document}