I think this is a stupid question but I'm going to ask anyway :-) Actually
it's on behalf of a friend of mine and I've told him it's not possible but I
thought I would check with the experts!

Is it possible to enter a number into a cell and have the cell display that
number multiplied by a given number in that same cell? I don't think this is
possible because of a circular error. I don't even know why he would want to
achieve this, he hasn't told me. Is there way of doing this at all - maybe
using VBA?