How to number examples automatically?

Question

I have document with 30 math examples. How do I number these examples automatically? Without using the list

 \begin{enumerate} ... \end{enumerate}

like

Example 1
blah blah

Example 2
blah blah

and so on?

Answer 1

• define new counter
• define new environment with title and number
• increment counter before its use

Something like this:

\newcounter{xmpl}
\newenvironment{example}
    {\noindent
     \refstepcouter{xmpl}
     \textbf{Example \thexmpl }
    }{\par\noindent%
      \ignorespacesafterend}

and then use as:

\begin{example} 
< content of the example>
\end{example}

Addendum: More simpler and straightforward solution is consider Christian Hupfer comment below: use of newtheorem.

• load package amsthm
• declare example environments as \newtheorem{example}{Example}
• use it as shown above

More details and concise description about theorems like environments you can find in Wikibook LaTeX/Theorems. Sorry, because I didn't recall for this usual approach before.

Addedndum 2: You can also use enumerate environment. Package enumitem offer simple redefinition of labels:

\documentclass{article}
\usepackage{enumitem}
\usepackage{lipsum}

\begin{document}
    \begin{enumerate}[label=Exercise \arabic*]
\item \lipsum*[11]
\[
c = \sqrt{a^2 + b^2}
\]
\item blah blah
\[
a = \sqrt{c^2 - b^2}
\]
\item blah blah
    \end{enumerate}
\end{document}

For other possibilities for formatting of enumerate environment see package documentation.

Of course this recent solution has sense if examples are organised as list, i.e. examples follow one after another.