I think that GetFormula is a great tool and very easy.
Once again, it gives you an easy tool to display both the formula and the value. If you change the formula everything updates automatically.
I have provided an example spreadsheet here:
You will have to trust me when I tell you I have inspected the file carefully and it has no harmful virus/macro.
All you have to do to make the function GetFormula available is:
From excel, Open up Visual Basic Editor (Tools/Macro/VBE).
Cut paste the following text into your Module1
Function GetFormula(Cell)
GetFormula = Cell.Formula
End Function
Return to excel (File/Close-and-Return-to-Excel)
Use the function GetFormula(cell-reference) in your spreadsheet
That function will be available to any spreadsheet whenever a spreadsheet containing that definition is open.