Thanks for everyone's input. I recieved a reply on the excel forums and thought I would share it with everyone here. In Excel if you want the inverse of MOD(7,23) and if A1 contains 23 and B1 7 then use this formula in C1 to get the inverse =MATCH(1,INDEX(MOD(ROW(INDIRECT("1:"&A1))*B1,A1),0 ),0) gives #N/A if there is no inverse

Yes I got maple to work from excel by using the maple add-in. Thanks I realize this is a maple forum, but I thought maybe everyone here having used excel at one time or another, and being mathematically inclined, might have found a way to get the inverse mod in excel without using the maple kernel. Not everyone has maple and excel is pretty much installed on every computer. Is there a way to do it?

Are you calling on Maple to perform the inverse mod function from excel? That's what it looks like. That formula doesn't work for me, at all. How do you get excel to call on Maple? I want excel to perform an inverse mod all by itself. Can it be done?

Well I didn't think it was that simple. Thanks! I'm trying to do the inverse MOD in excel, anyone know how to do that?

Thanks. Yes I want to wrap the letters. So lets say I wanted to do a shift of 5. I would use --- CharacterMap(cat($"a".."z"),cat($"g".."z",$"a".."f"), "shiftitfivespaces"); Is there a better way, where I can just change one number and the alphabet will shift accordingly?