Pages: Table of contents uses Arabic numerals only
When you create a document in Pages, you can add page numbers to your pages, and even choose a numbering format (such as 1, 2, 3; A, B, C; or I, II, III). If you create a table of contents (TOC) for your document, the TOC will always display page numbers as Arabic numerals (1, 2, 3), even if you selected a different format for your page numbers (such as if you chose the letter scheme A, B, C).
If your page numbers are not Arabic numerals, your document may be difficult to navigate since the TOC and page numbers won't match. As a general rule, you should use Arabic numerals to number your pages if you plan on including a TOC so that the TOC will reference page numbers correctly.
If you've used a different numbering format, you can edit your TOC using this workaround:
Export your document as an RTF (Rich Text Format) document (from the File menu, choose Export, then select the RTF radio button in the resulting dialog).
Open the RTF in Pages (from the File menu, choose Open or drag the RTF file onto the Pages icon in the Dock).
Manually change the numbers in the Table of Contents section so that they match your page number scheme.
Please note that some of your formatting may change during this process and may need to be corrected.