I have a figure in a cell which a whole column of formula refer to in order to calculate an answer.

I put a figure in that cell and all is well until that figure has to be changed.

Then, all calculations already made will change since the formula is now using the new number for its calculations.

Is there a way that I can tell excel to leave already calculated figures unchanged when a new reference figure is entered and to only use the new number for all new calculations?