Problems 1-5
Be sure you know which formula to use when calculating credit card interest, as well as the three methods for calculating the amount of interest.

Problems 6
You should know the number of days in each month. Some people remember this by remembering a poem, "Thirty days have September, October, and November. All the rest have thirty-one, except February ...." or by counting on your knuckles.

Problems 7-10
There are many problems throughout the text labeled IN YOUR OWN WORDS. Just relax. Do not be afraid to give your opinion. For the most part, these questions do not have "right" or "wrong" answers. You should spend about five minutes answering each of these questions.

Problems 11-24
These are estimation problems so they should not be worked with a paper and pencil or with a calculator.

Problems 25-30
See Example 1.

Problems 31-48
See Example 2 for calculating using the previous balance method.
See Example 3 for calculating using the adjusted balance method.
See Example 4 for calculating using the average daily balance method.

Problem 49
Read this question carefully. You are being asked to calculate the total amount to pay off the $30 loan. After you know this, then use I=A-P to find the interest. That is, the interest is the total amount to pay off the loan less the amount of the loan.

Problem 50
Use common sense to answer this question... don't look for some formula.

Problems 51-52
The Problem of the Day relates calculating interest on credit cards by putting the topic in an everyday setting.

Note: Homework Hints are given only for the levels 1 and 2 problems. You can also check some sources for homework help on the Internet (see Links, below), or you can call the author at (707) 829-0606 or send an e-mail to: smithkjs@mathnature.com