# Getting arrows underneath numbers

I want to draw curved arrows underneath my numbers, does anyone know how to do this? I've tried the command \curvearrowleft but TeX doesn't recognize that line, either because I don't have the package or the command doesn't exist.

What is the proper code for this red arrow underneath?

-
Have you checked the Comprehensive LaTeX symbols list? You will find some arrows when searching for \curve in several packages; for example \curvearrowbotleft in the mathabx package. If you actually want to use TikZ (why the tag?) we had a question about some little arrows … –  Qrrbrbirlbel Feb 9 '13 at 12:20
Welcome to TeX.SE. One possibility would be to adapt the solution from How to draw arrows from cell to cell at the borders of a table. –  Peter Grill Feb 9 '13 at 20:13

One possibility is the \curvearrowbotleft mentioned by Qrrbrbirlbel along with the accents package:

\documentclass{minimal}
\usepackage{mathabx}
\usepackage{accents}
\usepackage{xcolor}
\newcommand*{\uarr}[1]{\underaccent{\color{red}\curvearrowbotleft}{#1}}
\begin{document}
$\uarr{7}$.
$10.\uarr{5}\uarr{5}\uarr{6}$.
\end{document}


Here is a version with more visible arrow heads and less overlap with adjacent arrows, at the cost of more complication and a somewhat goofy-looking arrow head.

\documentclass{amsart}
\usepackage{mathabx}  % for \curvearrowbotleft
\usepackage{accents}  % for \underaccent
\usepackage{xcolor}   % for \color
\usepackage{graphicx} % for \resizebox
\usepackage{calc}     % for \widthof
\usepackage{bm}       % for \bm (bold symbol)
\newcommand*{\uarr}[1]{\underaccent{\resizebox{\widthof{#1}}{\height}{$\color{red}\bm{\curvearrowbotleft}$}}{#1}}

\begin{document}
$\uarr{7}$.
$10.\uarr{5}\uarr{5}\uarr{6}$.
\end{document}


\end{tikzpicture}% <-- important
}

\begin{document}
\tikzset{BottomArrowStyle/.style={thin, -stealth}}%
10.\tikzmark{Three}{5}\tikzmark{Two}{6}\tikzmark{One}{6}%
\DrawArrow*[red]{One}{One}%
\DrawArrow*[brown]{Two}{Two}%
\DrawArrow*[blue]{Three}{Three}%
\tikzset{BottomArrowStyle/.style={}}% restore to default

\bigskip
10.\tikzmark{ThreeB}{5}\tikzmark{TwoB}{6}\tikzmark{OneB}{6}%
\DrawArrow*[red]{OneB}{OneB}%
\DrawArrow[brown]{TwoB}{TwoB}%
\DrawArrow*[blue]{ThreeB}{ThreeB}%

\bigskip
10.\tikzmark{Three}{5}\tikzmark{Two}{6}\tikzmark{One}{6}%
\DrawArrow*[red,in=-85, out=-95, distance=0.2cm]{One}{Three}%
\end{document}

-
tikzmark like a boss. Great. –  percusse Feb 9 '13 at 23:41