Setting up tables --calculated fields??

[admin]

I am writing a small database to produce an automated invoice.

Here is a listing of fields:

InvoiceNum - Preassigned sequential number
InvoiceDate
DueDate
PayorName
PayorAddress
PayorContactPerson
BillableFromDate
BillableToDate
HCFACount
UBCount
TotalCount
CountFee
TotalDue
AdjustmentAmt
FinalDue
DateAmtReceived
Comments

I am thinking that this database could be 2 tables with the Payor Info in one and the Invoice info in the other. If you note there are several calculated fields Totals etc. Where do the calculated fields go in the tables? Thanks

Sheila E