## Wild About Math bloggers 1/7/11

[ The 1/14 Wild About Math Bloggers! post is at Equalis. ]

Happy New Year, Everybody! Here's some fun stuff from the Math web.

Shecky has an in-depth review of Princeton University Press's new book: Loving and Hating Mathematics.

Gary Davis at the Republic of Mathematics has a fun article about the number 2011. Not only is 2011 prime but it is also the sum of 11 consecutive prime numbers. Wow!

Keith Devlin has a very thought-provoking article, What Exactly is Multiplication?

After my three articles on the nature of multiplication in 2008 (June, July-August, September), I promised myself to leave the topic alone for some years. In fact, I never set out to write that series at all. The first one was in response to the unexpectedly widespread reaction I received to what I thought was a fairly innocuous, throw-away comment I had made at the end of an earlier column. In that initial posting, I had noted that it was not a good idea to tell students that "multiplication is repeated addition." It turned out that large numbers of teachers thought it was just that, so I was driven to post what ended up as three columns, each one longer and more in-depth than its predecessor, explaining why the "multiplication is repeated addition" meme (MIRA) is not only wrong but an educationally dangerous one to propagate. The danger was demonstrated in dramatic form by the large volume of correspondence I received, and the plethora of public blog-threads that ensued, which showed that a great many citizens fervently believe that MIRA.

Hat tip to Shecky.

Tanya Khovanova has a great nerdy joke at her Math Blog:

A note posted on the door of the tech-support department:

“Theory — you know everything, but nothing works. Practice — everything works, but nobody knows why. In our department we merge theory with practice: nothing works and nobody knows why.

Here's a slightly belated but nonetheless fun "Gauss Christmath Special" by Vi Hart.

Hat tip to Denise.

Ars Mathematica has a link to a Math Overflow thread about what exhibits the Museum of Mathematics should have. This thread is a great read because it has dozens of ideas about how to make Math come to life for the public.

Pat Ballew at Pat's Blog has "A Nice Property of the Medians of a Triangle".

We begin with a simple triangle, ABC, with opposite sides a, b, and c; and median AD which we will call m.

The object of the exercise; to find the length of the median, m, given the length of the three sides, a, b, and c.

Finally, I'll leave you with a great joke from Patrick at Math Jokes for Mathy Folks.

**Infinite Gifts**

A mathematician came across a lamp. He rubbed it, and a genie appeared. “Can I have three wishes?” asked the mathematician.

The genie had decided long ago that granting three wishes for his release was passé, and he generally refused such requests. With the holidays just around the corner, however, he was feeling charitable. “Okay, fine,” he said. “But agreeing to grant you three wishes takes care of your first wish, so you have only two remaining.”

The mathematician thought for a moment. It sure would be helpful to have a little extra money with which to buy gifts for my friends and family, he thought. “Okay,” said the mathematician, “I’d like a coin bag that is always full of gold; no matter how many gold coins I remove, there will always be some left.”

“Done,” said the genie as he handed the mathematician a coin bag.

The mathematician tried it out and, sure enough, no matter how many coins he removed from the bag, it always remained full. He was absolutely delighted.

“So, then, what would you like for your third wish?” asked the genie.

“Ah, well, that coin bag is awesome,” said the mathematician. “In fact, it’s so good, I’d like another one just like it!”

pat ballewJanuary 17th, 2011 - 11:12

Wow, very nice… in fact, I like it so much, I want another just like it…..