When you think of the wonders of the world, you think of Stonehenge, the Colosseum, and the Great Wall. Which are actually all feats of engineering...go STEM! Mr. Franklin called compound interest the Eight Wonder of the world and I do not know I did not hear about this till this past summer after listening to the Podcast "Stuff You Should Know."
The story goes, a French mathematician basically made fun of Franklin's Poor Richard's Almanack and mocked the American optimism that Franklin exhibited. Franklin, not to be made fun of, accepted the challenge and left 1000 British pounds to both Boston and Philadelphia in 1790 (year of his death.) Both accounts would earn 5% yearly interest and were not the be used till 200 years later (1990). At the end of the 200 years, the accounts were brought to courts on the legality but at the end Boston received $4.4 million and Philadelphia received $2 million. (Court fees lowed Philly's balance) Wow!
I had my students read an article about Franklin and the accounts as the start to the class and then we discussed the formula and more examples. It was a neat way to get my students to read math, introduce a topic, and tie in the content to history. I used this lesson in both my Advanced Algebra (Algebra II) and Common Core Coordinate Algebra. I still get comments from my students about it--and its been 2 months since!
Franklin's story is interesting and makes the math more relatable for students.
Links to articles:
Educator who loves math and working with students.