How to write under an underline?

Question

I would like to be able to write under the underline. Is it possible?

This is the simple code I have:

\documentclass{article}
\begin{document}
$\frac{ \textrm{Text}}{1} \frac{\textrm{Text}}{2} \frac{\textrm{Text}}{3}$
\end{document}

It does the job but I want to be able to make the texts under underlines smaller. One way to do so is to adjust the font each time. Is it an easier way? Or is there any built-in function for this. To assign the size which would be the same as the size for subscript.

Answer 1

It's always a good idea to write repetitive things in a macro:

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\newcommand{\underwrite}[3][]{% \underwrite[<thickness>]{<numerator>}{<denominator>}
  \genfrac{}{}{#1}{}{\textstyle #2}{\scriptstyle #3}
}
\begin{document}

See $\underwrite{\text{Text}}{1}\ 
  \underwrite{\text{Text}}{2}\ 
  \underwrite[2pt]{\text{Text}}{3}$.

\end{document}

The above MWE uses amsmath's \genfrac to create a fraction with \textstyle numerator and \scriptstyle denominator. You can, of course, add other functionality to it (like detecting the mode it's in and adjusting the size accordingly, say). Using \genfrac has the advantage of setting the fraction rule thickness; provided as an optional argument when using \underwrite[<thickness>]{<numerator>}{<denominator>}.

As reference, see section 4.11.3 The \genfrac command (p 14) in the amsmath documentation.

Answer 2

Do you want something like that:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
Hello \(\underbracket[0.3pt][0pt]{\textrm{my}}_{1}\) \(\underbracket[0.3pt][0pt]{\textrm{your}}_{2}\) \(\underbracket[0.3pt][0pt]{\textrm{our}}_{3}\)World!
\end{document}

Answer 3

You can simply use

\small{}

or

\tiny{}

to decreaase the size of your text.

Below is the improved version of your code:

\documentclass{article}
\begin{document}
$\frac{ \textrm{Text}}{\small{1}} \frac{\textrm{Text}}{\small{2}} \frac{\textrm{Text}}{\small{3}}$
\end{document}

Hope this helps :)