I want page 13 to show up as 12+1

Question

I am writing an important document which has ended up being 13 pages.

For superstitious reasons, I want the page number on the last page to show up as "12+1". In other words, I want the page numbers to be: 1, 2, …, 11, 12, 12+1.

How do I do this?

Welcome to TeX.SX! Please help us help you by providing a minimal compilable code example (MWE). — TeXnician, Sep 11 '18 at 10:10
And the question is currently at 13 upvotes, I like to imagine this isn't a coincidence. — LiefdeWen, Sep 11 '18 at 13:38
(salvaged from comment). This is a duplicate of https://tex.stackexchange.com/questions/87617/how-to-suppress-page-13 — , Sep 13 '18 at 15:36
@LiefdeWen You comment got 12 upvotes, so I upvoted it myself again, else nobody will dare. — , Sep 18 '18 at 13:06

egreg · Accepted Answer · 2018-09-11T10:28:14.433

49

Define a new counter format:

\documentclass{article}

\usepackage{kantlipsum} % for mock text

\makeatletter
\newcommand{\fixedarabic}[1]{%
  \expandafter\@fixedarabic\csname c@#1\endcsname
}
\newcommand{\@fixedarabic}[1]{%
  \ifnum#1=13 12${}+{}$1\else\number#1\fi
}
\makeatother

\pagenumbering{fixedarabic}

\begin{document}

\kant[1-50]

\end{document}

edited Sep 11 '18 at 10:28

answered Sep 11 '18 at 10:15

egreg

1,121,712

22

12+1 is much to obvious. I suggest $\sum_{i=1}^5 i -3$ . – Ulrike Fischer Sep 11 '18 at 10:18
2

For my own understanding, could you comment on the differences between defining a new counter format and only redefining \thepage as follows: \renewcommand{\thepage}{\ifnum13=\value{page}12+1\else\the\value{page}\fi}? (The latter also works.) – Max Sep 11 '18 at 10:25
1

@Max More general. – egreg Sep 11 '18 at 10:28
6

Many thanks! This worked. It was my first time posting a question here and I am amazed how quickly help came. Thank you all! – Amir Ali Ahmadi Sep 11 '18 at 10:49
@UlrikeFischer that evaluates to zero – Maya Sep 11 '18 at 14:49
1

@NieDzejkob No, to 12, which is different from 13 anyhow. ;-) – egreg Sep 11 '18 at 14:50
@egreg ;-). I should check my sums better. – Ulrike Fischer Sep 11 '18 at 19:00
@NieDzejkob It depends if one interprets it as $\sum (i-3)$ or $(\sum i) - 3$. As far as I know in mathematics there is not a convention set in stone for the operator precedence of summation symbols. – Federico Poloni Sep 12 '18 at 08:22
@FedericoPoloni True. Still, it is genuinely understood that unless obviously/specifically otherwise, $\sum a+b = b+\sum a$ . – yo' Sep 12 '18 at 09:00
\ifodd\thepage odd\else even\fi prints “even” on page 13. – Henri Menke Sep 12 '18 at 09:04
1

@HenriMenke Nobody should be using \thepage for testing with \ifnum: what if we're under \pagenumbering{roman}? Heiko Oberdiek's answer to the first listed question in the link clarifies this. – egreg Sep 12 '18 at 09:06
@egreg I know, that's why I linked the site search to show that people do this and sometimes even recommend this as an answer. Your thing should blow up if used in \ifodd to prevent such misuse rather than giving a wrong result on only one page of the document (\relax\ifnum#1... should do it). – Henri Menke Sep 12 '18 at 09:09
@HenriMenke If a user says \def\fi{\mathop{fi}} in order to define a math operator, they're on their own. Using wrong tools can lead to harm oneself. A way out could be using $12+1$ , but this could lead to page numbers being printed differently from the rest of the document; $\mbox{12}+\mbox{1}$ seems to me quite clumsy. – egreg Sep 12 '18 at 09:15

Fran · Answer 2 · 2018-09-11T10:21:04.537

17

It could be a complex solution to convert the counter page to "12+1" if the value reach 13, but if only matter when 13 is the last page, why not simply change the footer just before \end{document} to "12+1"?.

\documentclass{article}
\usepackage{fancyhdr}
\pagestyle{fancy}
\begin{document}
aaa 
\setcounter{page}{12} % this is the 12th page
\newpage
bbb
\cfoot{12+1} % this is the 12+1th page 
\end{document}

edited Sep 11 '18 at 10:21

answered Sep 11 '18 at 10:15

Fran

80,769

Thank you very much -- this is a quick solution too. The fancy page style created issues for me elsewhere, so I decided to go with the other proposed solution.
Many thanks everyone.
– Amir Ali Ahmadi Sep 11 '18 at 10:50
1

@AmirAliAhmadi the fancyhdr package allow a extensive control of page headers and footers so that issues probably can be solved with no effort, or maybe the footer can be fixed by another method without that package, but without a minimal working example showing these issues is not possible go further. – Fran Sep 11 '18 at 11:07

score 3 · Answer 3 · answered Sep 12 '18 at 06:29

The following solution sets page 13 as 12+1 in whichever format your page numbering is set to. It uses fancyhdr to set the page number in the Centre of the footer.

\documentclass{article}

\usepackage{lipsum,fancyhdr}

\pagestyle{fancy}
\fancyhf{}% Clear header/footer
\renewcommand{\headrulewidth}{0pt}% Remove header rule
\fancyfoot[C]{%
  \ifnum\value{page}=13
   $\mbox{\setcounter{page}{12}\thepage} + \mbox{\setcounter{page}{1}\thepage}$%
   \setcounter{page}{13}%
  \else
    \thepage
  \fi
}

\pagenumbering{roman} % Just as an example

\begin{document}

\sloppy\lipsum[1-50]\lipsum[1-50]

\end{document}

I want page 13 to show up as 12+1

3 Answers3