Assuming data in columns A & B.
In cell C1 type:   =A1-B1

With cell C1 selected double-click on the fill handle, lower right of cell.

George Gee

Numbers in column A

Numbers in column B

In C1 enter   =A1-B1

Double-click on the fill handle of C1 to copy down.

OR maybe you need..........

In C1 enter  =SUM(A:A)-SUM(B:B) which will not need copying down.

Gord Dibben  MS Excel MVP

if the first column is A and the Second B it will be in coulumn C this
get the formula active by typing =A1-B1 in Cell C1 enter select C1 and grab
the right
low courner of the cell C1, you should get a solid black cross, left click
and hold and drag down, this causes a relative copy of the formula. for mor
info and examples go to help files type relative copying.

Try this:
=SUMPRODUCT((A1:A200)-(B1:B200))

The result is (A1-B1)+(A2-B2)+(A3-B3)+.....+(A200-B200)

--
Rodrigo Ferreira
Regards from Brazil