excel adding error?

[h.]

is it possible that excel makes a calculation error when adding a column?

we have a spreadsheet with amounts and we are just using the simple autosum
formula to total them up. i have no idea why but if you manually add these
amounts it does not equal the total that excel has calculated. we have tried
many times and everyone is getting the same answer.

help!

 

[Gary''s Student]

You probably have a value in the column that only appears to be a number, but
is actually a Text value. SUM() will treat this value as zero.