Friday, March 11, 2011

Death to PEMDAS and There Is No Indigo

I have been a fan of role-playing games (rpg's) off and on since I was about 11 years old. Recenty I got into gaming again, after a hiatus of many years; I am currently playing an old-school Dungeons & Dragons campaign with my girlfriend Brenda and her sons. This blog post is not about gaming, though, except incidentally. As a result of returning to gaming, I have found a couple of really great old-school gaming blogs, one of which is Delta's D&D Hotspot. "Delta" is a mathematics professor (and rock musician) who lives in New York City; his blog posts often involve statistical analyses of game rules, or erudite discussions of concepts related to gaming (such as, most recently, the tactics of cavalry, pikemen, and archers).

Delta recently posted a surprising fact about the visible color spectrum:

Did you know that most color scientists no longer recognize "indigo" as a distinct color in the spectrum (as opposed to Newton's original 7-color scheme)?
I also enjoyed his screed against the ever-popular PEMDAS acronym:

Wednesday night, I walk into a lecture room for my first-evening algebra class of the spring. And what do I see on the chalkboard? Some motherfucker has oh-so-carefully written out the PEMDAS acronym, with each associated word in a column sequence. . . . among its flaws are (1) leaving out radicals as the inverse of exponents, (2)overlooking that multiplication & division are tied, and (3) overlooking that addition & subtraction are tied.
I ask you, if we can't rely on PEMDAS, what can we rely on? It makes one wonder how much of the information taught in schools and widely believed is (1) a gross over-simplification or (2) pure bunk. (In my own teaching, I've encountered a surprising number of incorrect beliefs relating to history and philosophy, many of which were picked up in schools.)
Post a Comment