how to insert page number with different format?

sometimes you want to insert different page number format, for example on several pages with format : i, ii, iii, and several pages with number like: 1,2,3. You can do that by following steps below :

1. put your cursor at the end of page.
2. select "page layout" tab, click "breaks", select "next page".
3. on next page, double click header (and footer).
4. unmark "link to previous". this make your header (and footer) not same as previous page.
5. thus, changing page number in this page doesn't change page number in previous page .