Reflection
	Personal comments on the learning experience:

This learning experience was developed as a way of teaching concepts of percents and compound interest in a "real world" context. I also wanted my 8^th graders to learn about financial responsibility and to begin planning for their futures (with credit card use, taking out loans, and saving for retirement some day).

I found this to be very successful. My students demonstrated that they could create practical spreadsheets and calculate compound interest. Not only did they show an understanding of simple interest, compound interest, and the differences thereof, but they also had a strong sense of how to save for retirement. Students were able to see (visually with Analyzer*) how a small, one time investment made early in life could be of more value at age 55 than a $15,000 investment invested at the same rate for 3 years prior to retirement.

Discussions in class went "down the retirement path" when we discussed IRA's, 401K's, and TSA's. I even had their interest (eighth graders!) when we discussed borrowing from a TSA to pay off 21% cards and then paying back your TSA at 8%. They seemed interested to find out that the former way gives 21% to the bank, whereas the latter allows the individual to collect the interest in his/her own retirement account (like borrowing from yourself and paying yourself back with interest.)

I found that 8^th graders are eager to learn about this and that the graphing aspect made the experience more visual and more real to them. Even those who did not demonstrate a proficient understanding of compound interest appeared to have a new respect for credit and its wise use.

Simple Interest & Compound Interest Spreadsheets {day 1}

Procedure for conducting this activity:

Simple Interest Spreadsheet:

Students will launch Microsoft Works and create a spreadsheet that calculates simple interest. It will be dynamic, so the proper interest will automatically be calculated when the percentage rate is changed.

Headings will include: "Principal" (or "Starting Balance"), "Interest Due", and "Monthly Balance".

Compound Interest Spreadsheet:

When Students become proficient and feel comfortable with the spreadsheet above, have them make a copy of that spreadsheet and then modify it to automatically make each monthly "Starting Balance" equal to the previous "Monthly Balance" (balance at end of previous month).

Now, have the students compare the values and use this information to discuss the difference between compound and simple interest calculations as a class. Continue the discussion enough to develop the concept of the compound interest formula as follows:

Products/Performances:

1) Simple Interest Spreadsheet: This contains monthly "Principal", "Interest", and "Monthly Balance" (total) columns.

2) Compound Interest Spreadsheet: This is the same as the spreadsheet above, but modified to reflect each former monthly balance in the current month's "Principal"("Starting Balance") column.

3) Modified Compound Interest Spreadsheet: {optional}

Multiple Representations of Compound Interest {day 2}

Procedure for conducting this activity:

Students begin by using scientific calculators to calculate the values of an investment at various points in time (they may use the scientific calculator desk accessory from a pull down menu) This will be done with both simple interest and compound interest (by formula). Next, students will use Analyzer* to graph both simple interest values and compound interest values for a given percentage rate and amount of principal. Students will then compare the graphs and discuss their findings as a class.

Next, as a class, determine the cost of half of a pack of cigarettes. Graph the curve that depicts a one-time investment of that amount at 7% over a thirty-year period. Make similar graphs (you can do six at once) by varying the percentage rate (Be sure to use only realistic rates if you want students to internalize their findings). Discuss the findings.

Next, discuss how investing a small amount at a young age is wiser than investing a large amount at an older age. Graph a one time $2,000 investment @ 9.0% to see its value for a forty year span. Next, compare that to $20,000 invested for 3 years at the same percent.

Review findings as a class, then proceed to work on credit card spreadsheets. An excellent discussion topic is that of how credit card interest grows exponentially and why banks prefer you make a very low, minimum monthly payment. This can be explored/modeled with the spreadsheet as well.

Products/Performances:

Graphs depicting many investments will be produced.

Credit Card Statement Generator {day 3}

Procedure for conducting this activity:

Students will use their spreadsheets from day 2 and modify them to incorporate the following: bank name, client name and account information, percentage rate, and columns for "Starting Balance", "New Charges", "Payments", "Interest", and "Monthly Balance".

Students will work to perfect a dynamic spreadsheet template and then print out the 4 required spreadsheets by altering information on the "template form" and using the "Save as" command to store statements for the 4 accounts.

Products/Performances:

1) Credit Card Statement for First Account: {$3,000 @ 15.9%}

2) Credit Card Statement for Second Account: {$5,000 @ 12.5%}

3) Credit Card Statement for Third Account: {$3,000 @ 5.9%}

4) Credit Card Statement for Fourth Account: {$7,000 @ 12.9%}

5) Electronic Copies: Students will submit the above printouts as part of a project and a disk containing the spreadsheet template file and the 4 account files (for teacher to verify that spreadsheets are dynamic and not "word processed").

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