How to subtract one field from another and sum a range of fields

I created a form in Word that I converted to a fillable pdf form using the prepare form feature for a template for a mileage log. I would like to create a formula that calculates miles driven for each row where it takes the odometer reading at destination point and subtracts the odometer reading at starting point. I know how to create the formula for the first row, however my table has 60 rows and I would like to copy the formula in the first cell to the cells in the other rows. Is there anyway to do this or do I have to create the formula for the cells in the other rows one by one? Also, I would like to create a cell that totals the miles driven for all of the rows in the miles driven column that will be labeled total mileage. Is there a formula that would allow me to do that? I have attached a template of the form I created to this post. If I can have assistance on this it would be much appreciated.