Algebra, schmalgebra.
All you need to know about earning interest and paying off debts is right here.

Loan Calculators	Real Estate Loan Calculators
Monthly Payments	How much house can you afford?
How much does that loan really cost?	Mortgage Refinance
Deferring Payment	Mortgage A
How will prepaying change my loan?	Mortgage B
How much does it cost to lease?	Convertible Balloon Mortgage
Rent vs. Buy	Bi-Weekly Mortgage Payment
Rebate vs. Low APR	Mortgage Payment Table
	Trasition to a Bi-Weekly Mortgage Payment
	Prepayment Mortgage Reduction
	Mortgage Qualification
Savings Calculators	Other Calculators
Simple Savings	How much estate tax will you pay?
Multiple Deposits	How wealthy are you?
IRA/401(k) Retirement	Prepayment vs. Investment
Nominal & Effective Interest Rates	Retirement Payout
Compound Interest Rate	What's your yield?
Future Value/Annuity	How much do I need tor retirement?