I guess the right thing to do this would be first to divide your paper into appropriate sections:
Insert – Section Break (tip: switch on Invisibles - View/Show Invisibles - to see where the sections start/end)
After that, you can go into a header/footer on the first page of first section and insert page numbers there (this will insert page numbers in every section).
Then, highlight the page number in the beginning of each section, go to Inspector's Layout tab (second pictogram from the left) and click Section. There you can configure whether page numbers in the current section continue from the previous one or are independent of it (under Page Numbers). Under Configuration you can choose whether the same header/footer format will be used in each section (tick "Use previous headers and footers"), or whether you want them to be different (untick it).
Finally, when you highlight page number and then right-click on it, you'll see options to use alternative numbering systems (romans, letters, etc).
And if you don't want page numbers in a particular section, just highlight and delete page number in a header or footer on any page in that section.