Stuart McLachlan
stuart at lexacorp.com.pg
Wed Jan 25 10:52:17 CST 2006
On 25 Jan 2006 at 7:24, Jim Lawrence wrote: > When tax totals are generated then all the tax subtotals are just added > together. In theory, all the subtotals could be added and the total tax > could be calculated but the answer would be wrong. This is the same problem > experience when trying to calculate the average by item and then expecting > the average for the whole group to add up. It never will. > No, the two are completely separate problems. Tax totalling problems are caused by rounding errors inherent in the process of working with currency which has a minimum sized unit (a cent or whatever). Averaging problems are caused by false assumptions about the underlying maths by the person writing the code. -- Stuart