## Wild About Math bloggers 3/18/11

I hope you all had a great Pi Day!

I learned from the 360 Blog that Brainfreeze Puzzles is running a Pi Day contest. No, you didn't miss the deadline. Entries are due on June 1, 2011. Check it out!

Vi Hart joins the Tau Day bandwagon with a great video, Pi is (still) Wrong.

Antonio Cangiano has a review of You Can Count on Monsters at Math-blog.com. Here's a brief description of the book from Publisher's Weekly:

This compact, innovative book counts to 100 using prime numbers represented as monsters, each with identifying characteristics (two resembles a bee with two buggy eyes, and three is an angry-looking triangular creature). The book opens with explanations of multiplication, prime and composite numbers, and factor trees, then moves on to a list of numbers. Each prime number looks unique, while composite numbers are represented by scenes involving their prime monsters (eight is illustrated as three of the beelike twos, i.e., two times two times two. Readers may have difficulty deciphering the pictures, which come to resemble little works of abstract geometric art. But especially for creative learners, visualizing the roles each monster plays may lead to deeper number sense. Ages 4 to 8.

## Discover Equalis and they’ll donate money to the relief effort in Japan

Equalis is the math-centric community that I've been blogging at for a number of months.

Equalis is the innovative on-line destination for the mathematics community. It provides the most vibrant and far reaching math-centric community on the internet, enabling the free flow of ideas, cutting-edge research, open source software, problem solving, open innovation and job opportunities for individuals and organizations with a common interest in math and math-centric endeavors.

Help Equalis to increase participation in their community and they'll contribute money to the Japan relief effort.

We have all been touched by the devastation in Japan. You can help us raise money for the relief effort just by using our website. Equalis will donate $1.00 to the Brother's Brother Foundation for each of the following through April 30th:

- Refer a Friend who registers with the Equalis Community
- Ask or answer a question in any one of the non featured forums
- Post your own Tip of the Day in any Open Source Software group
- Add a blog to any Equalis group

## Wild About Math bloggers 3/11/11

Welcome to the 3/11/11 edition of Wild About Math Bloggers!

The Mathematics and Multimedia Carnival #8 is up at DavidWees.com.

If you happen to be in the Santa Fe area, or know of someone who is, check out my Math Exploration Groups (aka Math Circle). I have one coming up Wednesday.

Salman Khan, founder of the Khan Academy, has a very inspiring TED video. His non-profit's ideas and software could revolutionize Math education, although I'm not a fan of doing lots of drills.

## Wild About Math bloggers 3/4/11

Welcome to Spring, at least here in Santa Fe, where it's 60 degrees! Just a few weeks ago it dipped to -10 degrees here. Onto Math ...

James Tanton has a really great, very accessible, four part introduction to the Partition Numbers and to the hunt for structure in these numbers. Here's the first video:

Patrick at Math jokes 4 mathy folks has a great puzzle:

Append the digit 1 to the end of every triangular number. For instance, from 3 you’d get 31, and from 666 you’d get 6,661. Now take a look at all of the divisors of the numbers you’ve created. What are the units digits of the divisors for every number created in this way? Can you prove that this result always holds?

Hat tip to Brent.

## Wild About Math bloggers 2/25/11

Welcome to the 2/25 edition of Wild About Math bloggers!

Shecky identifies two 'bite size' Math books.

There are a lot of 'bite-size' books out now that introduce readers to a range of key mathematical ideas without getting too technical or too deep (but not too simplistic either). Thought I'd just mention two of the ones I particularly like for anyone not already familiar with them

One of the books he mentions, 50 Mathematical Ideas You Really Need To Know, is a really excellent book. The other, Mathematics: A Brief Insight, is one I'm not familiar with.

Have you ever heard of nomograms? If not then you're in for a treat. Ron at Dead Reckonings reviews a new book, The History and Development of Nomography. Ron also has a nice introduction to nomography here.

James Tanton has a nice 3-part video on Curry's paradox and on area. Here's part one.

## Wild About Math bloggers 2/18/11

I hope you had a great Valentine's Day.

Denise at Let's Play Math has a nice post "Be My (Math) Valentine." Yes, by the time you read this it will be too late but you can start preparing for next year. Here's a YouTube video on how to make Mobius strip valentines. Denise has other ideas in her article.

Still on the Valentine's Day theme, 10-Minute Math has an article: Valentine’s Day heart graphs.

Antonio Cangiano has a nice post listing 30 great Math books as recommended by our readers.

## Wild About Math bloggers 2/11/11

[ The 2/18 edition of Wild About Math bloggers! is at Equalis. ]

Welcome to Wild About Math Bloggers!

Carnival of Mathematics # 74 - The Tungsten Edition - has been published at Walking Randomly. One link of particular interest was A cute result relating to sums of cubes. This article shows a great generalization of the formula: 1^3 + 2^3 + 3^3 + ... + n^3 = (1 + 2 + 3 + ... + n)^2. Be sure to read the comments to make the connection between the well-known result and the generalization.

March 1 is World Maths Day. What is World Maths Day? How does it work? When is the registration deadline? Denise at Let's Play Math tells all.

Irrational Cube has some nice visual illustrations of sums of geometric series. Here's one. Can you figure out what it demonstrates? [ Hat tip to Pat Ballew. ]

God Plays Dice has a nice article, Pixar Mathematics.

Pixar's use of harmonic functions (by David Austin) describes mathematical techniques used by Pixar. Incidentally, apparently there exists something called Pixar University, which I learned when I went to the excellent Pixar exhibit at the Oakland Museum of California. As far as I can tell they are not hiring, they're really an internal training program, and anyway I don't know anything about animation. (The exhibit's next stop is in Hong Kong.

Here's a video that illustrates the use of harmonic functions:

## Wild About Math bloggers! 2/4/11

[ The latest Wild About Math bloggers! is at Equalis. Here is last week's edition. ]

Welcome to February!

Speaking of February, Alex Bellos has a fun article about February, leap years, different calendar systems, the golden ratio and the golden string.

Science News explores the science of bike-sharing.

While the idea [bike-sharing] is gaining speed and subscribers at the 400 locations around the world where it has been implemented, there have been growing pains -- partly because the projects have been so successful. About seven percent of the time, users aren't able to return a bike because the station at their journey's destination is full. And sometimes stations experience bike shortages, causing frustration with the system.

James Tanton has a great new YouTube video exploration: A Leap-Frog Puzzle using Vectors (Tanton: Mathematics):

Choose any three points A, B and C in the plane. Starting anywhere you like on the page, "leapfrog" over the point A to land on the other side of A the same distance from it as you started. Now leapfrog over B, and then C, and then A again, and then B again and finally C again. Something astounding happens!

## Wild About Math bloggers 1/28/11

[ The current edition is at Equalis. ]

Here's the end-of-January edition of Wild About Math Bloggers! Enjoy.

Math Teachers at Play Carnival #34 is up at Math4allages.

One post in the Carnival that particularly got my attention was by John Cook telling us about an amazing lightning computing calendar produced by Ron D and available at the Dead Reckonings blog. It's free as a PDF download or you can buy a printed copy at Lulu.

Jon McLoone has a really fun article on using Mathematica for cracking ciphers using frequency analysis techniques.

NPR has an interview with Keith Devlin, the Math Guy, about a fun new book for kids on factoring integers into primes.

The book is based on this great poster.

## Wild About Math bloggers 1/21/11

[ The 1/28 edition is at Equalis. Here's last week's edition. ]

Welcome to another edition of Wild About Math Bloggers!

Alex Bellos introduces us to Lee Sallow's fascinating work with Geomagic squares.

[Sallow] realised that you could create a much more versatile magic square, which he calls a

geomagic square. Instead of containing numbers, it contains shapes, and that the combination of shapes that you get in each row, column and diagonal can be pieced together to make the same master shape.

Built on Facts has a nice introduction to the zeta function and on its relationship to prime numbers. Hat tip to Shecky.