## FoundAround 2008-21

Some miscellanea encountered this week:

• Personal Digital Mathematics Assistant. John Armstrong posted an image of an “ACME integrating pistol” over at The Unapologetic Mathematician, calling it the “perfect math gadget”. But maybe we could improve on it, have it do more than just integration? Just imagine how much better results we would see on the standardized tests if students could come in with an ACME MathZapper™. It might even let us “fix” the “all children held behind” mess (to borrow a phrase from Keith Devlin). “Here you go, Johnny. It’s your first government-issued Personal Digital Mathematics Assistant, complete with a preinstalled symbolic math package.” Who needs another browser war when we can have a winner-take-all brawl among Magma, Maple, Mathcad, and Mathematica?
• Blog brains. In a thread on the WordPress.com forums, I exchanged a series of posts with Jim Sizemore of Doodlemeister’s Weblog. After a brief foray into the world of HTML and CSS, he introduced the absolutely wonderful expression “blog brains” to refer to the technologies in question. I doubt I’ll ever look at tag soup in quite the same way again.
• Floating pennies (redux). Last month, I wrote about the perils of floating-point representations of currencies. Now there’s a related bit of discussion of sums in Excel over at Walking Randomly, based on a post at Office Watch. The main example uses—yep, you guessed it—the same two-place decimal representations that make floating point numbers not work well for currencies. It gets more interesting when one of the commenters implies that people using Excel for financial purposes shouldn’t have to worry about rounding errors. This just isn’t true, since accountants multiply by non-integer rates and they split money among multiple parties all the time—both of which introduce rounding error when getting back to pennies. Just try to divide a dollar evenly among three people. I’m sympathetic to the general sentiment, but neither rational representations nor packed decimal representations solve the currency problems (and weak data typing really just exacerbates the issues). *Sniff* *Sniff* Do I smell another Perspectives post baking?

### 2 Responses to FoundAround 2008-21

1. Jim says:

Hi Michael:
Who would have thought that a no-tech guy like me would get a mention on a theoretical math blog? Thank you for the “blog brains” attribution. And let me return the compliment for your “tag soup” line, or is that a commonplace with the html crowd that I’m just not aware of? (There’s so much in the blog world that I’m not aware of!) And thanks one more time for all your help on the forum the other day with my little problem.
Jim Sizemore
doodlemeister.com

2. Hi Jim,