This document discusses simple interest, how it is calculated, and examples of simple interest problems. It defines simple interest as interest calculated on the original principal amount for a period of time. The key formula provided is: Interest = Principal x Rate x Time. Several examples are shown calculating simple interest for different scenarios involving principal amounts, interest rates, and time periods. The document also discusses using simple interest formulas to calculate the maturity or future value after a period of time. Activity problems are presented at the end for the reader to practice calculating simple interest, interest amounts, and maturity values.