Say in Sheet2 start inv# is in A1 and finish inv# in B1;
Say in Sheet1, inv# is in column A and inv. amount in column B

In Sheet2, enter:
=SUMPRODUCT((Sheet1:A1:A1000=A1)*(Sheet1:A1:A1000 <=B1),Sheet1!B1:B1000)

HTH
--
AP

"Learning the hard way" a
écrit dans le message de news:
...
I have a worksheet containing the total of each invoice & then that gets
divided by two and placed into two seperate columns. I would like to
retrieve
the total of a given number of invoices by entering a start inv.# & a
finish
inv.# on a different sheet. Can anyone help me?