50th Carnival of Mathematics ~ Hosted by John D. Cook at the Endeavor blog Student Expectations Seen as Causing Grade Disputes (readers’ responses: ‘A’ Is for Achievement, ‘E’ Is for Effort) ~ “‘What would happen,’ I asked, ‘if a player showed up at spring training and worked harder than all the others yet still bombed? Would they…

## Multiplication of multi-digit numbers: a visual approach

Here’s a neat video showing a visual approach to multiplying muli-digit numbers. The algorithm is just a visual representation of the standard mechanical procedure that we all know, but somehow computing the product from these criss-crossed lines makes it look easier. One problem I see is that the algorithm may lead to confusion if there…

I’ve been on Facebook for approximately six months. I resisted for a long time, but caved in eventually. While there are many things I dislike about Facebook, it can be an interesting trip down memory lane (As Lev Grossman wrote in Why Facebook Is for Old Fogies, “son, we’ve lost track of more people than you’ve…

I think I will try something different. Once in a while (once a week?) I’ll post links to some of the articles I’ve read and enjoyed. I’m inspired by the beautifully simplistic Trivium.  In defense of j ~ It’s time to retire Euler’s choice of the letter i for the imaginary number √-1 The Arbesman Limit ~ People like to have things…

## Make your own polyhedral calendar

I realize that we’re already well into 2009. But I just discovered this link, so I thought I’d pass it along. You can use this website to generate a 12-month calendar (pdf or postscript) that can be printed and folded into a dodecahedron or a rhombic dodecahedron. It gives a few customization options (year, language, etc.). Enjoy!

## Happy Valentine’s Day

For your reading pleasure: The Calculus of Saying “I Love You”: Why you should never date man who knows more math than you.  (I wouldn’t say the mathematics is perfect, but it is fun to read.) Also, from xkcd.com:

Tomorrow (2/13/09) is both Friday the 13th, a scary day for those of you with paraskevidekatriaphobia, and it is also 1234567890 day. What is 1234567890 day? At 6:31 pm EST tomorrow, the Unix time will be 1234567890. That is, exactly 1234567890 seconds will have elapsed since midnight Coordinated Universal Time (UTC), January 1, 1970, not…

## Is this the Cayley table of a group? (Part 2)

In my previous post I posed the following question: suppose you are given a table for a binary operation such that there is a two-sided identity, every element has a two-sided inverse, and the table is a Latin square (that is, each symbol occurs exactly once in each row and each column). Is it the Cayley table of a…

## Is this the Cayley table of a group? (Part 1)

A math major in our department business major asked an interesting question the other day. The student’s abstract algebra class was working with Cayley tables. The class was given a table for a binary operation and was asked to check if it was a group. Given a table it is easy to check that the…

## LaTeX bugs in WordPress

Terrence Tao wrote a blog post today about LaTeX bugs in WordPress. He suggests compiling a list of all bugs so that WordPress can work on them. I had already discovered the closed bracket bug that Tao describes. I have also encountered a bug similar to the one mentioned in the first comment to Tao’s…

## Fibonachos

I wonder how many readers of the Sunday funnies understood the Foxtrot cartoon this morning. (Update: for those of you who landed on this page looking for a definition of the term “Fibonachos,” go here.)

## Math on a bridge

God Plays Dice posted a link to a photo of some mathematics displayed prominently on a bridge. (No not that bridge.) Below is the photograph of the mean value theorem on a bridge in Beijing. Does anyone know the story behind this? [photo by Vmenkov published under the Creative Commons Attribution ShareAlike 3.0 License]