Select cell C3 and type an equal sign to begin the formula. Type the equal sign followed by the constants and operators up to 8192 characters that you want to use in the calculation. If you have a lot of numbers the better idea is to use the SUM function.
Check out the following image.
The formula below subtracts the value in cell A2 and the value in cell A3 from the value in cell A1. Click on the cell where you want the result of the calculation to appear. In Excel we can use this concept to add and subtract in one formula. Create a simple formula in Excel.