I have an error-checking formula in a spreadsheet:
"If(Sum(A1:A30)<D1,"ERROR","Balanced"), where A1:A30 are values that are
entered from a source document, while D1 is the Total listed on the same
source document. The purpose is to ensure that all component parts are
correctly entered. All values are formatted as #,##0.00.

There are random times whereby the sum of A1:A30 results in a number such as
25.0000000001 which does not equal the Total of 25 that had been entered
into D1. Since the above formatting displays 25 for both values, the only way
of combatting the issue is to use a Round function for the Sum.

How can this happen when there is no division involved and all components
are entered as dollars and cents?

Excel version 2003.

Your help is greatly appreciated,

Sam