rounding to what? The default is a long number field, have you tried changing your field to a currency or double field? This has more decimal places....
You will have to be a bit more informative if this doesnt resolve your issue
As the Mailman said, the important thing here is to change the Field's Field Size from the Default of Long Integer (Integers are WholeNumbers and have no Decimals) to either Single or Double, depending on how large a Number you're trying to store in the Field. If you want 2 Decimal Places you'll have to set that Property; the Default is 'Auto,' not two.
Setting the Format to Currency isn't going to change a Field defined as a Number/Integer to a Field containing Decimals.
bboss - why have your posts to date always been answering threads that were posted MONTHS, or YEARS, ago? And, in one case the answer had already been accepted and worked. So it was a pointless post.