1) The document discusses simple and compound interest, with simple interest increasing at a steady rate each period and compound interest increasing at a geometric rate where interest is calculated on the growing balance. 2) Simple interest uses a fixed multiplier to calculate interest for each period, while compound interest uses a changing multiplier based on the growing total balance. 3) Compound interest will always produce a higher total than simple interest over multiple periods given the same initial balance, since the interest earned also earns interest.