# How to make curved arrows

I am a math teacher and I still have a hard time getting started with Latex, but I would like to know if someone could help me on how to generate the following example. Researching on the internet I found that I can use PSTricks for the curved lines but I still don't understand how to make the continuous and dotted lines, as well as putting the whole example in a box, since I have always had the problem with the dimensions of the boxes where I put the examples. A simple solution consists in creating empty nodes with an offset in the denominators of the fractions, and connecting them with the \ncarc command:

\documentclass{article}
\usepackage{pst-node}
\usepackage{sansmath}

\begin{document}

\sansmath
{$\frac{3}{\pnode[0.5ex, -0.5ex]{a}5} + \frac{1}{\pnode[1ex, -0.5ex]{b}10} = \frac{6}{\pnode[1ex, -0.5ex]{c}10} + \frac{1}{\pnode[1ex, -0.5ex]{d}10} = \frac{7}{10}%\ \psset{arrows=->, arrowinset=0.12, arcangle=-40, dash=3pt 2pt} \ncarc{a}{c}\ncarc[linestyle=dashed]{b}{d}$}

\end{document} • Thank you very much for your help, but when I copy the codes in overleaf I get the annoying "undefined control sequence", could you please explain to me why? @Bernard – OscarR Oct 10 at 20:47
• @OscarR: What is this undefined control sequence? – Bernard Oct 10 at 21:16
• @OscarR are you compiling with pdflatex? That won't work, pstricks needs latex +dvips. – Ulrike Fischer Oct 10 at 21:29
• Or simply xelatex. – Bernard Oct 10 at 21:31