I confess, I really like 7th graders. I seem to
have found the right combination of being super-
strict, having engaging mathematics to work on,
and telling provocative stories. It's the stories,
though, that are the most convincing reason for
them to come to class.
Yesterday we were learning about simple
interest compared to compound interest. Before
launching into formulas and such, we were
having an informal discussion about when
interest comes into play in the real world and
what kinds of questions they could ask their
parents to learn more about the effect of interest
rates.
We talked about how banks give you interest as an incentive for storing your money there, and turn around and lend your money to someone else, while charging them interest. Students almost angered to discover that the money they put in the bank isn't the exact same money which they receive when withdrawing from an account. "But that was MY money..."
One question led to the next and we started talking about advantages of banks and why you might have a lot of cash and NOT deposit it into an account. I dug into my suitcase of courage and found the perfect personal story. When in college, I spent a year in Bolivia and often had large amounts of cash stored with me during my travels. In considering how to hide it, I decided (male readers, please excuse my bias here...) that most robbers are men and most men avoid women's feminine products at all costs. So, I used a box of tampons, threw away some of the tampons, and stored my cash rolled up inside the wrappers.
I hadn't thought about that story in years, but the spontaneous telling of it was quite a hit and I doubt that class will ever forget how to calculate interest as my Bolivian tale led into the teaching of interest as the 'alternative method to storing money in a tampon wrapper'.
