How to print a past value of a counter

Question

I have this counter which I have defined using \newcounter{myCounter}.

Printing the value of myCounter can be easily done via \arabic{myCounter}. How can I print the value of (myCounter - 2)?

Answer 1

Either use the \label-\ref system if you're stepping myCounter via \refstepcounter system, or manually calculate it via \numexpr:

\documentclass{article}
\newcounter{myCounter}

\begin{document}

\setcounter{myCounter}{5}
\verb|\themyCounter:     | \themyCounter

\verb|\arabic{myCounter}:| \arabic{myCounter}

\bigskip

\refstepcounter{myCounter}\label{myLabel}
\verb|\themyCounter:     | \themyCounter

\addtocounter{myCounter}{2}
\verb|\themyCounter:     | \themyCounter

\bigskip

\verb|\ref{myLabel}:     | \ref{myLabel}

\verb|Calculation:       | \number\numexpr\value{myCounter}-2\relax

\end{document}

\the<counter> is usually used to represent the value of <counter>, and is defined as \arabic{<counter>} by default. As reference, see The \the command.

More options exist (with LaTeX's fp and LaTeX3's l3fp) if you want to perform more intricate calculations.