There is plenty of humor, a few movies, some great activities and explorations, and lots of math in

**Math Teachers at Play 17**. Hope you enjoy reading these as much as I did. Thanks to everyone who submitted posts or answered my requests to include their work.

First, a bit of administrativa: Please see this post at Walking Randomly about the rebirth of the

**Carnival of Mathematics**, and some upcommng scheduling changes for

**Math Teachers at Play**.

David Richeson at Division By Zero has brought us a great list of activities that are likely to inspire a few budding mathematicians in his post Kindergarten Mathematics.

In her post, Elementary Math isn't Easy, Joanne Jacobs directs us to a recent article on the importance of elementary mathematics and elementary math teachers by Hung-Hsi Wu in

*American Educator*.

Rachel M encourages us to grow a Counting Garden posted at quirkymomma.com - an activity that helps reinforce basic counting and number recognition.

Mathematics is everywhere, particularly at the breakfast table. At Math with My Kids we are reminded of the challenges and rewards of mathematical discovery in Math with Bannanas. Rick Regan suggests an interesting and edible

*100 days of school project*in his post One Hundred Cheerios in Binary at Exploring Binary.

Kakie presents Teach kids how to make $1,000,000 in 30 days with pennies! posted at Bur Bur & Friends: Community Blog. Keeping with the economics theme, Kendra offers Pumpkin Patch: Piggy Bank Math Game posted at Pumpkin Patch.

Much has been written on math blogs lately about how to understand and explain "negative multiplied by a negative is positive." On this fruitful theme, Brent Yorgey presents Minus times minus is plus posted at The Math Less Traveled. Jason Dyer gathers many of the threads that this question has spawned together and offers his own explanation in Negative times negative posted at The Number Warrior.

Denise offers some guidance in How to Solve Math Problems II posted at Let's Play Math!.

Sue Van Hattum offers a way of tackling the problem of math anxiety in her post Math Relax: A Guided Visualization for Overcoming Test Anxiety in Math at her blog Math Mama Writes.

You may have heard of the "Jigsaw" method in collaborative learning, but what about the "Speed dating" method? Kate Nowak introduces this structure in her post Speed Dating at f(t).

John Golden presents a dynamic geometry exploration of the Pythagorean Theorem, considering all triangle types in GeoGebra: Triangle Tuning posted at Math Hombre. See his GeoGebra introduction in an earlier post here. You may also want to see Kate Nowak's instructions for putting your GeoGebra into your blog here.

Kimberly Lightle's post, Dynamic Math and Science Learning With Simulations, at Exemplary Resources for Middle School Math and Science and Maria Andersen's post, Interactive Simulations from PhEt, at Teaching College Math both provide some great links to online simulaiton software. Sue Vanhattum of Math Mama Writes tells us about an early pioneer of learning math through computer interaction in her post Mindstorms: Children, Computers, and Powerful Ideas.

Liz at STEM-ology has pointed us towards a new resource and recruitment program for mathematics teachers,

**Math for America**, in her post X plus Y.

Another math resource has been provided by the Mathematics Department at BYU, which announced that their site When Will I Use Math? has launched. This perrenial question was also answered by Deb Russell in her post Math: When Will I Ever Use This Stuff?, which points to an article on mathematics and 3D animation.

In Pandemics and Their Numbers, Terese Herrera points us to an H1N1 inspired lesson created by The New York Times at the blog Exemplary Resources for Middle School Math and Science.

Humor and mathematics go hand in hand in several recent posts.

Pat Ballew offers a little tongue in cheek math talk in You Might Be a Mathematician IF... posted at Pat'sBlog.

Xi at 360 presents some great math comics the posts All about A4, Another Math Comic, and How About Another Comic?. Luke Kane points us towards some other recent, and very slick, math comics in his post Comics and Math at Logic Nest.

At Komplexify, we have a bit of calculus poetry in the post Calculus Haiku - The Derivative.

Mistakes, ambiguities, the unexpected, and the impossible - math teachers encounter these, from time to time.

Jakie points out how mistakes often turn into teachable moments in her post When Sketchpad is Wrong at Continuities.

Glowing Face Man presents Ambiguities in Mathematics posted at Glowing Face Man.

Sam Shah shows us some examples of functions behaving badly in his post sin(1/x) at Continuous Everywhere but Differentiable Nowhere.

Vlad Alexeev shows us an impossibly small book of impossible figures in the post Mini Books of Anatoly Konenko at his blog Mathematical Paintings and Sculptures.

John Cook has posted on the math behind musical scales in his posts Circle of fifths and number theory and Circle of fifths and roots of two at his blog The Endeavor.

Alison Blank has put together an inspired and inspiring

*Prezi*presentation, Math is Not Linear, and posted about it on her blog Axioms to Teach By.

Maria H. Andersen of Teaching College Math has put together another impressive prezi presentation and linked to it from her post How can we measure teaching and learning in mathematics?

The Albany Area Math Circle lets us know about the math documentary Hard Problems: The Road to the World's Toughest Math Competition. To find out more about Math Circles, check out the National Association of Math Circles site.

Green Fuse Films had another math-film announcement on their blog:

**Between the Folds**, their documentary about the math and art or origami, is now available on DVD.

Reidar Mosvold lets us know about what looks like a really neat event: Maths Week in Ireland on his blog Mathematics Education Research Blog.

Marjorie Morgan presents her thoughts on Outdoor Education and Mathematics teaching in her post Lindsay & Sharon - outdoor adventurers at GO! Girls Outdoors.

It surprises some that guessing and measuring can both fall under the mathematical umbrella.

Tom DeRosa presents The Very Exact Science of Guessing posted at I Want to Teach Forever.

Maria Miller presents 10/10 and the Metric Week posted at Homeschool Math Blog.

Staying with a metric theme, Austen Saltz, a senior high school student who is blogging at Talking Science, points us to Nikon's Universcale in his post The Size of the Universe. Universcale is very reminicent of the Powers of 10 film from the 70s, but much flashier (see the film here).

Two approaches to thinking about breaking sticks and making triangles are found at Bill the Lizard and Pat's Blog. Bill takes a simulation-based approach in his posts, The Broken Stick Experiment and The Broken Stick Revisited, while Pat explains how to tackle the problem using limits in his post, A Limit Approach to a Classic Geometric Probability Problem.

Thanks to everyone. If you submitted an article that was not included, or if you have a post that you think would have made a nice addition, please consider submitting it to the next installment. The next

**Math Teachers at Play**will be up at Math Mama Writes on October 30th.