RE: 3D Formulas
Hello Jayne
Thank you for your question and welcome to the forum.
A 3D formula is a formula that refers to/references the same cell on more than one worksheet.
There is quite a comprehensive explanation and instructions on how to create a 3D formula here:
http://www.bettersolutions.com/excel/EED883/QN620422111.htm
I hope this helps.
Kind regards
Amanda