KenKen

Christina sent me a link about a cool new puzzle called KenKen. It is Sudoku-like, but involves arithmetic as well. Here is board. This is my understanding of the rules. A four by four board can be covered in the numbers 1 through 4 with no more than 1 of each being each row or column (like Sudoku). However, the board is divided into subregions or rectangular boxes. Take the first two boxes in row 1. That is a subregion. The two and division sign say that only the two numbers that occupy the box have to have a quotient of two. So you could fill in 4,2 or 2,1 for the first two boxes. Interesting, huh. And for teachers this could be a fun puzzle to work with classes. (In fact it was invented by a Japanese teacher.) The Times even has a lesson plan for you, or play just for fun online. Thanks Christina!

Math-Toon

Laura G. tipped me off on Sunday's Foxtrot's Fibinacho action.

Flight of the Conchords

I'm a sucker for any math visualizations of personal lives. Sue told me about a show she watches: Flight of the Conchords. I'll spare you the weak premise, but there are two musicians and a manager. The manager in last night's episode decides that their relationship should go from being strictly professional to friends. The funny part of this is the completely business-like manner in which the manager tries to accomplish this transition. Why am I interested? He uses a graph to explain. His theory is that the closeness of relationship is proportional to the amount of time one spends together. (That would of course make your coworkers your best friends, but don't get hung up on the details.) Here is a Youtube clip of the description. (You'll have to fast forward to about 1:53.)



Later in the show, the musicians have failed miserably at being friends. Here is the manager's graphic summary of the duo's blunders. (Fast forward to the 6:00 min mark.)



Thanks, Sue!

Venn's for Sue

Sue's class is doing Venn Diagrams, so I thought I'd include a two more of my favorites. There are a ton of funny/cute uses of Venn Diagrams. It is definitely the one part of math that has stuck for every graphic designer.

Explain your next breakup with a Venn Diagram. Fuffer on Flickr


I call this the intersection of snarkiness.(You'll probably have to blow this one up to see it.)


This is pure wise-assery. Kevan on Flickr


Also, check out my personal favorite in this previous post.

You Venn Again

Look what I found in Rolling Stone. Party like a math-star.

Twitter's Rising Popularity < Twitter's Rising Cost ?

I picked this up on a data mining feed. A really interesting discussion is brewing on how much it costs twitter to maintain it's network. The worry is that users getting SMS messages are going to eat the network out of house and home as the network gets larger. Here is a really simple demonstration of where the worries come from. Say it costs twitter $100 a year to maintain a the correspondence between any two users.



One can see adding a third user increases the overall cost of the network by $200. Adding the fourth will increase the cost by $300. You see where this is going. The fifth member will increase the cost by $400...and the nth member will increase the cost by (n-1)*100.

Now Twitter's actual case is much more complicated. First, each new member doesn't connect with every single old member. Second, some links cost more than others. Third, the more members, the greater twitter's add revenue (I assume they are add-based). This helps offset the greater costs.

Curious? Here is Paul Botin's post that started the discussion.

I came a cross the discussion reading Mathew Hurst's critique of Botin describing the growth of costs as "exponential". The math snark in me also laments the imprecision with which this word is often used.

Figuring Out the X Hex

For all you math educators, Christina sent this on to me. You might be interested sitting in on this seminar.

Free Live Webinar:
Why Students Struggle with Algebra and How Schools Are Helping
When: Tuesday, February 10th at 1pm Eastern time.
Free registration is now open at: http://edweek.org/go/algebra
One of the biggest challenges in K-12 education today is how to help students overcome their struggles in introductory algebra. Many students fail or are barely able to keep up in their first algebra course, typically taught in 8th or 9th grade. In response, state and school district officials are trying to solve this problem in several ways, such as by encouraging better teacher preparation, including an emphasis on algebra, and by revamping courses and curricula to help struggling students, such as through the creation of "algebra readiness" classes aimed at girding students for the challenges of that class. In addition, policymakers at all levels have called for an improved, more streamlined approach to teaching elementary and middle-grades math as a way of preparing students for algebra.
This webinar will bring together a number of experts who have examined students' experiences with algebra. One of the goals is to explore the fundamental question: Why do so many students find algebra so difficult? The webinar will then examine efforts by districts and private curriculum-developers to help these students. It will also touch on major developments at the national level in this area, such as the release last year of a report of the National Math Advisory Panel, which called for more coherent math curricula at early grades as a foundation for algebra.
About the Guests:
Jon R. Star, Educational psychologist and assistant professor of education Harvard University.
Mary Jo Tavormina, Elementary Mathematics Manager, Chicago Public Schools.
Jesch Reyes, Math specialist, former algebra teacher, Chicago Public Schools.