|In column B cell 1 use the formula|
Then drag the formula down all 3312 rows.
Once you have all your subtractions done,
You need to change column B from a column of formulas to a column of real values,
First, highlight column B from cell 1 to cell 3312,
then on the Task Bar,
Select: Past Special,
You could, if you wished, paste the values to A directly but
I would advise you NOT to until you have checked everything
in column B and are sure it's what you want.
Then simply copy column B to A