Excel Help

[Jokester]

Bit stuck on how to do this in excel, what I want to do is create a rolling average type calculation.

Cell A = My new value
Cell B = My old value
Cell C = 0.2x Cell A + 0.8x Cell B

The trick that I want is that when I enter a new value in Cell A I want it to calculate the new value in Cell C, copy it to Cell B and then clear Cell A ready for entering a new value.

Does this make sense?

 

[Jokester]

Cheers, doesn't quite do what I'm looking for, but I can see how it works so I should be able to tweak it.