So you’re like: “What do you guys know about Forever Stamps?”
You ask, with a grin that can only be described as money-grubbing, “Are you guys thinking what I’m thinking?
One of your students almost certainly is.
You set the up the scheme.
Depending on your grade level and calculator availability, you a) have ’em derive the equation or b) just show ’em that these things are predictable and that the price is rising.
You run the calculations and you build that sucker up. “I’m about to make all of you filthy rich,” you say, with your finger ready to drop like a hammer on the wireless remote.
“Ninety freaking dollars!”
“220% return on investment!”
“In only 25 years! Tell your parents! It’s better than stocks!”
And then you let them tear down your house of cards with a flurry of objections, including a) the inevitable total teeter-tottering of personal communication from postal service to e-mail, b) the difficulty of storing 100 stamps in mint condition over c) 25 years for d) a paltry reward which at that time won’t be worth but a few Twizzlers.
You let ’em tear you down because a) your retirement’s locked up in sturdier investments, and b) these discussions, the kind stirred up by reckless mathematics, are the last pin holding this thing together as we clatter towards the finish line where, if I have my way, we’ll still be finding math in odd places.
This slide deck took an extra hour to cook up but, man, such a worthwhile investment. More than any other year I want to work this one straight through to the last bell of the last day. I can’t figure out a finer finish.