### Oh, P.S.

Yesterday I posted some ramblings about presenting rational-number arithmetic to battle-scarred victims of the math wars. But I left out the saddest part. Here it is: the expensive calculators required for this class can carry out the computations in question (${2\over3}-{1\over4}$ and ${6\over7}-{5\over8})$ very easily! The code for the first, e.g., is “2/3 – 1/4$\rightarrow$Frac” (the “Frac” feature is the first option in the “Math Menu” and so requires two keystrokes; everything else is right there in front of us on the keypad—and just as it appears on the printed page, with no “implied parenthesis” or what have you [by way of contrast, in order to code, e.g., ${{5x -1}\over7}$ one must recognize that the “fraction bar” acts as a “grouping symbol” and enter (5X-1)/7; the usual mistake—5X-1/7—of course represents $5x -{1\over7}$ according to the “order of operations” conventions … and all this might very well seem sort of overwhelming, I suppose]).

And I’ve more or less begged ’em, over and over, to use their calculators for these problems! (“When you’re working out homework problems, you should do the calculations by hand for practice—computing with fractions is a big part of our course [and algebra more generally]; when you’re in a hurry or—on exams or quizzes, say—need to check your work, by all means, break out the computer … look, it’s this easy …”)

And I say this that’ll never grow tired of denouncing the pernicious influence of all this high-tech folderol on math ed. Yep. That’s the saddest part. Meanwhile, as I was hinting earlier, the most will-sapppingly frustrating part is having to show up every day and talk about this kind of stuff in the face of what seems like pretty ample evidence that whatever I say is not only ignored, but actively resisted. It beats working, I guess.

#### 1 Comment

1. this paper looks potentially useful.
pretty badly garbled by my browser, however.
my main man h. wu is of course also very good on fractions.

• ## (Partial) Contents Page

Vlorbik On Math Ed ('07—'09)
(a good place to start!)