1. How can I remember how to do proofs by induction when each one is so different?

Although each induction problem is different, they all involve the same basic method. Study the notes and examples carefully and learn the method.

2. What is the difference between simple interest and compound interest?

Simple interest is calculated over a period of time and paid out and the principal amount remains constant.
With compound interest the interest generated over each time period is added to the principal amount.

3. How can I work out simple interest and compound interest?

There are formulae involving these two types of interest, the variables used include P(the principal), r(the interest rate/ time period) and n(the number of time periods).