%
% numbered.tex
%
% (c) 2022 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule
%
\documentclass[8pt,a4paper]{article}
\usepackage[final]{pdfpages}
\usepackage{geometry}
\usepackage{times}
\geometry{papersize={210mm,297mm},total={180mm,260mm},top=21mm}
\usepackage{fancyhdr}

%\topmargin 20pt
%\oddsidemargin 20pt

% from the TeXBook, page 308, exercise 7.7
\def\ifundefined#1{\expandafter\ifx\csname#1\endcsname\relax}

\pagestyle{fancy}
\ifundefined{sectionnumber}
\cfoot{\sffamily\Large\thepage}
\else
\cfoot{\sffamily\Large \sectionnumber{} -- \thepage}
\fi
\renewcommand {\headrulewidth}{0pt}

\begin{document}
\includepdfset{pagecommand=\thispagestyle{empty}}
\includepdf[fitpaper=true,scale=0.95,pages={1}]{unnumbered.pdf}
\setcounter{page}{1}
\includepdfset{pagecommand=\thispagestyle{fancy}}
\includepdf[fitpaper=true,scale=0.94,pages=2-]{unnumbered.pdf}
\end{document}