Number equation as 0.1 instead of 1

I am using book class for my thesis. I have a preface which is before the first chapter. In this preface, all sections are numbered like 0.1 etc. However, equations are numbered as 1 instead of 0.1, which looks strange. How can I ask LaTeX to number my equations in preface like 0.1, 0.2, etc, please? Thank you!

• Sounds strange that you want sections numbered 0.1, wouldn't unnumbered sections (\section*{...}) be better for the preface? – Torbjørn T. Oct 19 '15 at 10:12
• Could you provide a minimal example with the preface, to make it easier to answer your question? In the mean time, you could take a look at, e.g., tex.stackexchange.com/questions/61756/… to get started. – Marijn Oct 19 '15 at 10:12
• @TorbjørnT. If I use \section*{}, i.e., no numbering of sections. What should I do with the equations, please? Should I leave it as 1 instead of 0.1? What is the common practice? – LaTeXFan Oct 19 '15 at 10:15
• So far un-asked: Why do you have equations in the preface at all? And, do these equations need to be numbered? – Mico Oct 19 '15 at 10:17
• As far as i see it, the preface should have a few common introductory words. The real deal happens in your mainmatter. – Johannes_B Oct 19 '15 at 10:26

As long there is no clear setup: Perhaps this one?

\documentclass{book}

\usepackage{chngcntr}

\begin{document}

\counterwithin{equation}{chapter} % Use chapter as driver for the resetting

\section{A section}

$$E = mc^2$$

$$c^2 = a^2+b^2$$

\chapter{Real stuff}

\section{A section}

$$E = mc^2$$

\end{document}


• I am convinced of not using 0.1 and alike. Just look not so nice. – LaTeXFan Oct 19 '15 at 10:43
• @LaTeXfan: If you want to have 0.1 -- it's there now. I wouldn't it for my personal usage, as well as 0. sections – user31729 Oct 19 '15 at 10:48
• Yes. Thanks for that. As I wrote earlier, I agree it does not look good. But if I use \section*{}, is it good to number equations 1 and so on? Remember in later chapters, all equations will be numbered like 1.2 and 2.2 etc. – LaTeXFan Oct 19 '15 at 10:54
• @LaTeXFan no problemo. You'd refer in the text to equation 1 or 5.17, noone gets confused. But a preface with equations important enough to warrant numbering (and referencing) sounds strange. Perhaps use unnumbered equation*? – vonbrand Feb 16 at 2:44

Place \renewcommand\theequation{\arabic{equation}} just before your equation.

Example:

\renewcommand\theequation{\arabic{equation}}
$$\label{eqn:eq1} X = 1+5$$

• Welcome to TeX-SX! As a new member, it is recommended to visit the Welcome and the Tour pages to be informed about our format. However, your post is not really answering to the original question. – R. N Feb 10 at 12:44