How can I build a macro that return the absolute value of an argument of another macro? I would like that the \abs macro return the absolute value of the its argument.


So whether I use a positive or negative number as argument, the expression \abs{#1} will always be positive.

  • 2
    \newcommand{\abs}[1]{\ifnum#1<0 -\fi#1} – egreg Jun 14 '14 at 22:42

--1 is legal in \numexpr, equivalent to 1. So

\newcommand{\absval}[1]{\ifnum#1<0 -\fi#1}

is what you're looking for. Then


will do.

  • Shouldn't it be \abs instead of \absval in the first snippet to be compatible with the second one? – Henri Menke Jun 15 '14 at 0:30
  • @HenriMenke Yes, it should. ;-) – egreg Jun 15 '14 at 8:32

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