A family of Microsoft word processing software products for creating web, email, and print documents.
Are you talking about the numbers on the pages that contain the table of contents or the page numbers that are displayed in the table of contents?
If the latter, what format has been used to the page numbers in the body of the document? The page numbers displayed in the Table of Contents and usually in the same format as the page numbers in the body of the document. Are they of different formats in your case?
To change the format, expand the Page Number drop down in the Header & Footer section of the Insert tab of the ribbon and select Format Page Numbers and change the Number format in the Page Number Format dialog that will appear.