If youre completely new to Excel you can learn how to create simple formulas in our completely free Basic Skills course. You need to take the sign - as the subtraction sign. IF A20B2-C2A2 The above formula says.
The solution to subtract several numbers with a number without using a formula is to use special paste.
The cell reference appears after the equal sign. To indicate if a month should be subtracted you can enter a minus sign - before the number eg. Simply use the SUM function to shorten your formula. For example input 25-5 in the function bar and press Enter.