How to Remember Pi
You may be wondering why I used the spelling of the dessert in my title rather than the spelling of the Greek letter. The problem is that had I written, “How I wish I could calculate pi,” I would have been rounding improperly and wouldn’t have helped you with how to remember pi.The title of this article is one of many mnemonic devices that people use to remember the digits of the number π. There are, respectively, 3, 1, 4, 1, 5, 9, and 3 letters in the words of my title, and 3.141593 is a more properly rounded approximation of πthan 3.141592.All around the world, on Pi Day (March 14th, for obvious reasons), people show off how many digits of π they can recite from memory. There are people who have memorized tens of thousands of digits, usually using mnemonic tricks not unlike the one above for how to remember pi.It is a testament to our love of patterns that anyone would bother to care about the digits of π beyond the first few dozen. Ten decimal places are enough to calculate the circumference of the earth, were it a perfect circle, to within a fraction of an inch. Thirty digits or so are enough to calculate the circumference of the known universe with a precision that you would need an electron microscope to notice. So, there is no worldly or otherworldly reason to know the 2017th digit of π. Still, it’s kind of cool when somebody does.Though there are many and varied mnemonics that cover some of the digits of π, my favorite is a reimagining of Edgar Allan Poe’s The Raven. It was created by Mike Keith and goes on for 740 words (digits) if you disregard all punctuation. Here is a sample:
Poe, E.: Near a RavenMidnights so dreary, tired and weary.Silently pondering volumes extolling all by-now obsolete lore.During my rather long nap – the weirdest tap!An ominous vibrating sound disturbing my chamber’s antedoor.“This,” I whispered quietly, “I ignore.”I encourage you to look up the rest – it is remarkable. Happy Pi Day! Make sure you integrate some pizza or apple-cranberry pie into your diet, and, while eating it, be sure to calculate its circumference and ponder your digits.(Many of the fun facts in this post are borrowed from David Blatner’s The Joy of π )
