## Friday, May 21, 2010

### Math Teachers at Play 26

Welcome to Math Teachers at Play 26!
Coming to you from Michigan, the 26th state of the union, admitted on the 26th day of 1837.  (Did they do that on purpose?)  Of course this doubled the original 13 states, since mathematically, 26  is 2x6th Prime.  (Credit.)

The US flag of 1837 is at left.  The 2 sets of 13 stars pick up the 13 stripes well, don't you think?  (Of course, things went south with the 27th state.)

## Puzzles

Case Ernsting wrote about Quines in the programming language Ruby at his MetaSpring Blog.  This is a quick bit of interesting logic about self-referential programs that he connects to other interesting mathematics, including Godel and Nerdsniping.

jd2718 presents Puzzle: continued root (Part 1) and  Puzzle: continued root (Part 2) posted at JD2718, saying, "This might be a puzzle, this might be teaching, this might be advanced (advanced algebra)."  It's a good teaching tale of engaged students.  Jonathon writes a lot about many issues surrounding teaching.

Hmm.  This will be the only Math Teachers at Play ever directly after a square and before a cube.  (Proof.)  Of course, in a 3x3x3 cube, only 26 cubes are visible, so you're really taking the 27th on faith.  I guess that makes 26 the third Rubik's Cube number?   If 8 is the previous and 56 is the next, what is the fifth Rubik's Cube number?  What is the closed form for the nth Rubik's Cube Number?

Iron sharpens iron.

David Ginsburg presents An Important Point About Teaching Decimals posted at Coach G's Teaching Tips.  Just a quick note about saying your decimals correctly.  Have your students taught you any bad habits?

## Shana Donohue shares So, how much do I owe you? posted at The ZeroSum Ruler, saying, "My eleventh graders still struggle with adding positives to negatives. On the last quiz, the top student in the junior class solved a logarithmic equation incorrectly because she evaluated "x - 3x" to be "-4x". To combat this huge misconception, I created the ZeroSum ruler"  She'd love comments and suggestions.  Not sure where to put this - she is plugging a product, but seems to be really thinking about this tough content.

Hmm.  The 26th US President was Teddy Roosevelt.  Robert Talbot, a math prof at a liberal arts college, wrote a post about what teachers can learn from Teddy's daily schedule.  Can you think of any other good Teddy math connections?

## Elementary

NerdMom presents An enhanced Sieve of Eratosthenes posted at Nerd Family, saying, "Both our 8 and 6 year olds have been taking the long way around factoring (both fractions and multiplications) so NerdDad helped them make an enhanced Sieve of Eratosthenes."  (If you don't click you're bound to suffer some NerdGuilt.)

Ian Byrd presents iPods, Apple Stock, &Authentic Math posted at Byrdseed Gifted Lessons.  He found some nice data and made it into an authentic problem (a la Dan Meyer) all while preparing students for a state assessment.

Cynthia presents Table TOP Math - make tops, learn math, have fun! posted at love2learn2day.  These look fun.  You have to write for the pdf, but she has video of the tops in action.

Rivka presents Infinite evens and odds. posted at Tinderbox, based on some recent family investigations s'purred on by The Cat in Numberland.

Ashley Allain presents Above Average Fun With the iPod Touch: Merging Gymnastics and Math posted at HyperHomeschool, saying, "This goal of this activity was to integrate math, technology, and our daughter's love of gymnastics creating an authentic learning experience."

## Secondary

Ryan O'Grady presents Wheel Spin posted at Maths at SBHS.  He took a disappointing result from a test and turned it into a lesson using video to gain understanding into the problem.  Very nice.

Tom DeRosa presents Use a Dartboard to Review Geometry and Probability posted at I Want to Teach Forever.  Fun variation on the usual review games.  Reminds me that 26 is the score on darts that can incite mockery.  Because the dartboard has 20 between 5 and 1, a poor thrower will hit 5-20-1.  He also shares a do-it-yourself tetris set, that could easily be adapted to many of your own whiteboard objects.

Guillermo P. Bautista Jr. presents Introduction to the Concept of Functions « Mathematics and Multimedia posted at Mathematics and Multimedia.  He's got some great exploded illustrations of cubes.  (This is the post to read if you're trying and at all stuck on the Rubik's Cube number problem I placed above.)

Kitten presents Cops and Robbers *coughcough* posted at Kitten's Purring, saying, "Today for math, I did a graphing game on the computer called: Cops and Robbers."  This is a great example of self-extension.  One question leads to another leads to taxicab geometry ...

Hmm.  The 26th amendment gave 18 year olds the right to vote in the United States.  How many people in the  country can vote today because of this?  I can't make Wolfram|Alpha tell me, although I'm pretty sure it must know.

John Chase presents Heat Conduction in a Rod posted at Random Walks, saying, "I built a little geogebra applet to graph the heat distribution throughout a rod. You can change the initial heat distribution function, ask for the distribution at any time, and change the temperatures applied at each end. The math requires an understanding of differential equations and fourier series, but the *results* can be understood by high school math students."  Nice support using technology to make content more accessible.  So hot it's cool.  (I just couldn't resist...)

Fëanor presents Irrationality posted at JOST A MON, saying, "Another proof for the irrationality of sqrt(2)."  It's a historical proof by contradiction from early last century.  (Reducto ad absurdum just sounds like a Potter spell, though.)

Edmund Harriss presents Hexayurts and African Villages posted at Maxwell's Demon, described as "Some thoughts on mathematical thought."  He finds math in an anthropology situation and then connects it to all sorts of other ideas, including fractals and lolcats.

Host's Prerogative
Some of my favorite blog posts from the recent past.
Dan Meyer's TEDx talk has caused a furor quickly, even getting him on CNN.  I embedded it here because I was showing so many people.   Rare to see one item really move the conversation forward.  Thanks, Dan!

I read everything Kate Nowak writes, because she's funny, honest and insightful.  Check out Fail for an example.

The last host (MTAP 25) has a post about How to Teach Curiosity at Point of Inflection.
Sue Van Hattum has been working more on her book than blog, but still found time to contribute a nice piece on reading a math book.

Maria Anderson has her plenary address from the Michigan MAA conference up.  Tech to delight and excite.

Hmm. Since there are 26 bones in the human foot, I tried my best to find something 26ish about the 2010 World Cup.  Best I could find was that it's the jersey number of deposed English captain John Terry.  Can a true futboler help me out with a soccer connection?

By the way, I stumbled across a great source for number facts, including 26.  I had found or worked out many of this issue's factoids, and then found this resource - doh! (As a total aside, but on that page, Einstein had a great 26th year. "Albert Einstein (1879-1955), publishes 5 papers in Annalen der Physik (1905)  on the photoelectric effect, statistical mechanics, Brownian motion, special theory of relativity, and relationship between matter & energy: E=mc2" That might be the best year ever for an academic.)

Thanks for visiting!
That concludes this edition. Submit your blog article to the next edition using the carnival submission form.  Past posts and future hosts can be found on our blog carnival index page.

Hope you enjoyed it!  Have a look around while you're here.  Besides Mr. Meyer's talk, I've been showing people this riff on the mac/pc ads for students vs. learners.  I'm asking for people to share their favorite math songs, and have been thinking about multiplying fractions too much.  So maybe you shouldn't look around...

Best of the Spam
If I included yours here and it is not spam, my deepest apologies.   Or if I somehow missed your submission, please let me know and I'll correct the situation.

10 Essential Web Tools for Teachers
Top 50 Special Education Blogs

1. Wow! This looks great! Thanks, John. (Lately, I've usually read most of the posts mentioned in MTAP, but this time they're mostly new to me. It'll take me hours to get through all these goodies.)

2. Hi Math Hombre! I followed a link from my blog back to yours. Thank you for writing a bit about my ZeroSum ruler. What is it about negatives that makes them so difficult? I always think about the teacher from Stand and Deliver and his "fill the hole". I wish it were that easy! For years I asked students, "which number his bigger" when they were solving a problem like "-12 + 7" but how misleading and just plain WRONG! But asking, "which of the two numbers has a larger absolute value?" was always such a mouthful and would just send me on a tangent explaining absolute value. My ruler uses absolute value in a way that's not so obvious to be distracting while also making solving "-12 + 7" very easy. Absolute value is the best!

3. Nice curating! Thanks for including me.

4. Hi John. Lots of great stuff here--I'm so glad to have my post included!

5. I was impressed with the variety of submissions this month. Is that the end of the school year cleaning up impulse?

Thanks to all the submitters!

6. thanks john for including my site. i am planning to have my own blog carnival. it will mostly tackle the integration of computers and technology in teaching mathematics.

I would appreciate if you will announce it in your blog.

the address of my blog is

http://math4allages.wordpress.com

7. I want to thank you for writing about my blog. I check my stats regularly and many days there is traffic from your site. Thank you.

8. That's not me - that's the wonder of the carnival!

It's definitely worth sharing. Hosting is a bit of work, but it's also definitely good for traffic to your site.

9. Hi guys. I'll be starting a new Math Carnival. You may want to check it out:

http://math4allages.wordpress.com/2010/05/27/blog-carniva/

10. Hi Math Hombre! I created some animated math videos that I'd like you to know about. The latest is on factoring trinomials with A>1. You can see them all, as well as an old music video from our school's students (not math related, but fun!) on my YouTube channel...