Sum Value Not Correct?

[nehpets12]

If I use the sum function to add up 6932.8 2321916.3 -2321916.3
It gives me the wrong answer

If you copy paste spiecial value you get 6932.79999999981 on the formula bar Very strange does anyone know why it does not work?
I have tried excel 2003 and excel

Book1
	A	B	C	D
1	6932.8		6932.8
2	2321916.3		2321916.3
3	-2321916.3		-2321916.3
4	6932.8		6932.79999999981
Sheet1

 

[VoG]

This is caused by the inherent imprecision of floating point arithmetic http://support.microsoft.com/kb/78113