I have some prices in cells A1 to A20 I know how to get the average price if
all the cells have a price in it, but how do I get an average if say only
some of the cells have the information in them.
ie if 10 cells have a price and 10 cells dont I could divide by 10 to get an
average but this will obviously change as I add more prices in so looking
for a way to avoid me having to manually adjust the average figure each time
I add a new entry.

thanks