We're all familiar with the basic concept of setup and payoffs: early on in your screenplay, you set up some detail/scenario that may seem irrelevant, but later on will yield a result that hopefully your audience wasn't anticipating (the payoff).
Most debt settlement letters include: The date, name, and address of the credit card company. A notation after the address that this is regarding a hardship letter. The credit card number and amount of the debt. A short statement of your financial situation, why you're in that situation, and why full payment is a hardship.
The formula for calculating simple interest is A = P x R x T. A is the amount of interest you'll wind up with. P is the principal or initial deposit.
Lenders multiply your outstanding balance by your annual interest rate but divide by 12 because you're making monthly payments. So if you owe $300,000 on your mortgage and your rate is 4%, you'll initially owe $1,000 in interest per month ($300,000 x 0.04 ÷ 12).