On 19 Feb., 17:48, "Fred Smith" wrote:
It's rounding. When you see 67.42 in a cell, the actual value may be 67.416.
Excel rounds this to 67.42 because you asked for 2 decimal places to
display, but still uses 67.416 in the Sum calculation. When you have more
than one cell like this, your results are off by a penny.

To fix the error, put =round(...,2) around your formulas.
...

Round(sum()) can still be different from sum(round()). If you need to
"fix" this:
http://www.sulprobil.com/html/largest_remainder.html

Regards,
Bernd