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
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.
Their is always a solution to any problem.