\documentclass{article}
\begin{document}

This is the first paragraph.

\section{First Section}

Preamble of Sect.~1.

\subsection{A Subsection}

Here some text, an inline formula $(a+b)^2=a^2+2ab+b^2$, as well
as a displayed equation
%
\begin{equation}
e^{\pm ix}=\cos x \pm i \sin x\;,
\end{equation}
%
and some more text.

Now some verbatim text \verb|a b c|.  That's all, folks.

\end{document}