You'll have to use two cells: one for the user to enter either their own
value or the suggested value, a separate cell for the suggestion. Lets say
you want the user to put their choice (either their own number or the
suggested one) into cell A1, and you want the suggestion to show up in cell
B1. So in cell B1 you would put something like:
=IF(A1="",(1+2+3)/4,"")
put your formula between the commas where I've put (1+2+3)/4, that just
represents your formula for coming up with a suggested value. So, while A1
is empty, your suggested value will be displayed in B1, but when something is
entered into A1, B1 will go blank. Note that 0 (zero) in A1 is not the same
as "".

You cannot put the formula into the same cell that the user is going to put
their number/choice into because as soon as they do that, the formula is
deleted, never to return except by typing it in again.

"G_Engineer" wrote:

I am trying to use a spread sheet to "suggest" values for cell by use of a
formula. However, I would like the user to be able to enter any value in a
cell. If the user deletes his value, I would like the original formula to
recalculate the "suggested" value.