So that all browsers show the same thing, special symbols (those with an ASCII code greater than 127 should be coded as entities, either entity names or as numeric references (AKA entity numbers).The numeric reference is built using the characters &# followed by the ASCII decimal code followed by a semi-colon, as in the examples above.
Use the menu item Insert->Symbol, find the symbol to be inserted and click it.The ASCII code is shown in the centre box at the bottom of the Insert Symbol dialogue, with the drop down menu to its right set to ASCII (decimal).
Note that if the Insert button is used, the symbol will be inserted as a character, not as an entity or numeric reference - symbols entered as characters may not display correctly in some browsers,and display may be affected by HTTP headers provided by some servers.See Symbols and Page Encoding for more details.
There appears to be a bug like feature in FrontPage 2003 where Reformatting HTML in code view converts most common entities into characters.This is not a good thing. See Symbols and Page Encoding for a possible workaround
See http://www.w3schools.com/tags/ref_entities.asp for a full list of entities, and alternative methods of coding them.