Function adds .0000000001 to my sum.

[casecase6]

I made a spreasheet for a coworker to use. I tested the formula out on my computer and it all worked fine. She gets errors like ...(124)-(123)=(1.00000000000001)

As far as i know, we both have the same version of excel 2010...

I have them set as Currency to 2 decimal places, the "sample" shows that the answer will be "$1.00" but it shows up "1.0000000001"

[shg]

Your computer (and therefore Excel) uses binary floating point arithmetic, which cannot store most decimals exactly. Use ROUND.