1. Simple interest is interest paid on the principal amount only and not on accumulated interest. The simple interest formula is I=PRT, where I is interest, P is principal, R is interest rate, and T is time.
2. Compound interest is interest paid on the principal as well as on previously accumulated interest. The amount of compound interest is calculated using the formula A=P(1+R/n)^(n*t), where A is total amount, P is principal, R is annual interest rate, n is number of compounding periods per year, and t is time in years.
3. An annuity is a series of regular payments made at fixed time intervals. The