Manuel can pay for his car insurance on a monthly basis, but if he pays an entire year's insurance i

Manuel can pay for his car insurance on a monthly basis, but if he pays an entire year's insurance in advance, he'll receive a $40 discount. His discounted bill for the year would then be $632. What is the monthly fee for his insurance?

His full bill F, is denoted as:
F - 40 = 632

If we add 40 to each side, we get:
F = $672