Tag Archives: exponential

Project/Journal 11

This was the year’s largest and most technical writing assignment. I required students to submit drafts which I edited and returned to them so they would have the chance to make their writing more precise. The project consumed a large chunk of our time, but the process of explaining their methods and results in writing, getting a draft edited, then trying to make their language more precise was a turning point for my students’ mathematical communication.

All but one of my students were seniors and were pretty well invested in learning about student loans. On Day One I introduced subsidized vs. unsubsidized student loans. (The project presents case studies using unsubsidized student loans.) I also addressed how student loan interest is actually calculated* and explained that A=Pe^(rt) would give good enough approximations. In the mish-mash curriculum I worked from, A=Pe^(rt) is used as an application for the natural log, so I wanted to give students experience using that formula even though the unit was not connected to other types of interest growth.

The project gives 3 cases:

  1. You take out an unsubsidized student loan of $3000 your first semester of college and it grows while you attend school for 5 years.
  2. You take out that same loan but you make an early payment of $500 two years into college.
  3. You take out the same loan but a semester later.

*09/10/14: An improvement might be to ask students to give estimates or judgments on the three options before any calculation.

The first day’s assignment was to calculate what the debt would grow to by graduation in each case and estimate the cost of repayment. I left students pretty much to their own devices to figure it out, which frustrated them to no end.

On Day Two we compared their solutions, went over the correct solutions, and they worked on the first two paragraphs of the write-up, turning in drafts the next day. Then they worked on the edits and writing the next paragraph, turned in a new draft, etc. (See what I mean? Large chunk of our time.)

Although self-conscious about it, I decided to provide a scripted template for the write-up for two reasons: to get them to wrap their brains around formal technical writing before requiring them to produce it themselves, and to allow them to focus on the portions I cared about most without completely doing away with the rest. The first paragraph is almost entirely scripted, with just a couple blanks to fill in. The other paragraphs allow much more freedom. I’m sure the template could be improved, so don’t judge! However, feedback is welcome.

Editable version of the assignment sheet: Ch. 12 Student Loans Project

Editable version of the template for the write up: Ch. 12 Studen Loans Write-up Template

Ch. 12 Student Loans Project Image

*Unfortunately, my initial understanding of how student loan interest accrues was faulty. I was able to get this explanation from the bank managing my husband’s student loan:

Student loans are considered simple interest loans. Interest accrues daily on the outstanding principal balance.
The calculation used to determine the amount of interest that accrues per day is as follows:

Total Unpaid Principal Balance x Interest Rate, Divided by 365 or 366 (Days in a Year)