\documentclass[a4paper,10pt]{scrartcl}

\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{amsmath}

\begin{document}
\section*{Test 1}
Hi, this is some text...

\newpage
\section*{Test 2}
... and \textbf{bold} text,
\textit{italic} text ...

\newpage
\section*{Test 3}
... and some well known math:  $c = \sqrt{a^2 + b^2}$

\newpage
\section*{Test 4}
\begin{center}\begin{itshape}
 nested environments ...
\end{itshape}\end{center}

\newpage
\section*{Test 5}
\begin{align*}
c^2 &= a^2 + b^2 \\
c &= \sqrt{a^2 + b^2}
\end{align*}



\end{document}

