That's the way computers work. They work in binary, we work in decimal.
There are imprecisions in the translation process, as you've found out. If
you want a specific precision, use the Round function, as in:
=round(yourformula,2)

Regards,
Fred


"chitown29" wrote in message
...
In Excel 2003 and 2007, why, when adding 664,199.05 and negative
582,911.61
the answer comes out 81,287.4400000001? Why is there a 1 at the end?
This
causes issues when building formulas to control two sets of information
that
should equal one another.