The default form is to use arabic numbering. If we include a tableofcontents in our document, then as the document grows so will the table, and when this spreads to further pages this will alter the page numbering for subsequent pages throughout the document.
A simple solution is to use roman numbers for the pages preceding the first chapter, as was shown in the root file used as an example in the previous section. The switch back to arabic numbering must then be made after the start of the first page. So the command
\pagenumbering{arabic}
must follow either a \newpage command at the end of the
preamble, or appear after the first \chapter command.