# Dots in equation environment not appearing

When I enter a number, for instance 10.2 in either an equation environment or within $...$, the dot is not appearing and instead I get an empty space. So for instance, I've typed:

$d_p = 5.12 \cdot 10^{-4} m$.


and what I get is: 5 12·10−4m.

I'm using a template, so there are many packages. For math and symbols I'm using the following:

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{fixmath}
\usepackage{array}
\usepackage{units}
\usepackage{trfsigns}
\usepackage{textcomp}
\usepackage{gensymb}
\usepackage[integrals]{wasysym}
\usepackage[version=3]{mhchem}
\usepackage{ziffer}
\usepackage{dsfont}
\usepackage{upgreek}


Does anyone know why this happens?

• Even looking into the chrystal ball of wisdom does not reveal an answer unless you provide your document. – user31729 Apr 3 '17 at 12:39
• You have a hungry dot eater in your computer. And seriously: please prepare a MWE, so we can reproduce your problem. – Przemysław Scherwentke Apr 3 '17 at 12:39
• @ChristianHupfer hah sorry guys, kinda new to this. I've added some more details, but not sure if it's enough? – egil137 Apr 3 '17 at 15:56
• Hi egil137 welcome to the site: Please read this post and do your best to follow the advice. Construct the MWE and see if the problem is still there. If you add \documentclass{article} \begin{document} $d_p = 5.12 \cdot 10^{-4} m$. \end{document} to your MWE you've provided and the problem goes away, then it's not enough. P.S.: Seems like it is enough – Au101 Apr 3 '17 at 15:58
• Well, simply by commenting out lines in your preamble it's the ziffer package that's doing it, I can tell you that. And this is precisely what ziffer is there to do: click if you don't want that behaviour, why are you using the package? – Au101 Apr 3 '17 at 16:00

The reason for this is the ziffer package, which exists precisely to achieve this behaviour:

The pack­age mod­i­fies the be­haviour of char­ac­ters in maths mode so that:
‘.’ is used as a one-thou­sand sep­a­ra­tor (as is com­mon in Ger­many)
‘,’ is used as a dec­i­mal sep­a­ra­tor (as is com­mon in Ger­many)
‘--’ is rep­re­sented with spac­ing as ap­pro­pri­ate to such con­structs as ‘1.000,--’.

https://www.ctan.org/pkg/ziffer?lang=en

You can see this working if you modify your example:

$d_p = 5,12 \cdot 10^{-4} m$.


So the . is being used to provide a small space to separate the thousands.

$d_p = 5.120.000$.


This is what ziffer is for, if you do not want this behaviour, you should not load the package.

In other news, if d_p is a length in metres, you should consider using the siunitx package to typeset it. The metres sign should never be italic and it needs to be separated from the value:

\documentclass{article}
\usepackage{amsmath}
\usepackage{siunitx}

\begin{document}

$d_p = \SI{5.12d-4}{\metre}$.

\end{document}


• ziffer is a package that should not used at all, in my point of view – user31729 Apr 3 '17 at 16:15
• Many thanks! I will definitely get rid of that package. – egil137 Apr 3 '17 at 16:26