Curved Line Under Number (not sure what it's called)

Question

How would I make something like this in Latex?

Thank you in advance!

Answer 1

You can use the \underbrace command or using mathtools the \underbracket command:

\documentclass{article}

\usepackage{mathtools}

\begin{document}

You can try $1\!\underbrace{666\cdots6}_{m\textup{ 6's}}$ or $1\!\underbracket{666\cdots6}_{m\textup{ 6's}}$

\end{document}

If you want a round brace with the text through it, you can use the abraces package (documentation here):

\documentclass{article}

\usepackage{abraces}

\begin{document}

A special underbrace for $1\!\aunderbrace[l1@{\raisebox{-2pt}{\smash{\scriptsize\,$m$ 6's\,}}}1r]{666\cdots6}$.

\end{document}

Or if you want the text lower:

A special underbrace for $1\!\aunderbrace[l1@{\raisebox{-4pt}{\scriptsize\,$m$ 6's\,}}1r]{666\cdots6}$.