problem with adding columns of numbers

In a worksheet I have a series of numbers in a row tabulating a percentage.
In the last column I want the percentages added and displayed below. I used
SUM to add the proper cells and yet the total displayed is off by $0.02. Any
ideas why?

Take a look at

http://www.mcgimpsey.com/excel/pennyoff.html

In article <4BDDCFDF-EA22-4DAB-B635-14D29D460ACA@microsoft.com>,
jeri_g <jerig@discussions.microsoft.com> wrote:

> In a worksheet I have a series of numbers in a row tabulating a percentage.
> In the last column I want the percentages added and displayed below. I used
> SUM to add the proper cells and yet the total displayed is off by $0.02. Any
> ideas why?