Or 1 - (a/b) ;) The rational behind my choice of a/b - 1 is that it corresponds exactly to what I was asked to display in an accounting report and use it to fil

Or 1 - (a/b) ;) The rational behind my choice of a/b - 1 is that it corresponds exactly to what I was asked to display in an accounting report and use it to filter some lines. I would be happy if you can elaborate why it makes more sense to you :)