When I sign-up to host the May edition of Math Teachers At Play blog carnival organized by Denise of Let’s Play Math blog, I didn’t know it will be its 50th edition. Wasn’t I lucky? It’s a milestone for MTAP. Kudos to the organizer and supporters of MTAP. But I got one little problem. It is a tradition in math blog carnivals to always starts with saying something mathematically significant about the *n* in its *nth* edition! Oh dear. Things I associate with the number 50 are mostly non-mathematical like golden anniversaries!

Wikipedia to the rescue:

**Fifty** is the smallest number that is the sum of two non-zero square numbers in two distinct ways: 50 = 1^{2} + 7^{2} and 50 = 5^{2} + 5^{2}. It is also the sum of three squares, 50 = 3^{2} + 4^{2} + 5^{2}.

And I didn’t know that until I hosted this carnival! I’m a teacher I have to ask: “So what’s the next bigger number to 50 that is the sum of two non-zero square numbers in two distinct ways?”; “What are other numbers that can be expressed as a sum of the squares of consecutive numbers?”; “What about those numbers that can be expressed as sum of cubes?”;… There is always something to investigate in math. One of the major objectives of school math is to get students into this thinking habit without us telling them to do so but I’m digressing from my topic now. Let’s get to the great posts submitted for this edition.

1 - How many bricks are in this building? Says its author Paul Murray: This is an activity I’ve used for years and recently wrote up for a class. It integrates many problem-solving methods, multiplication, addition, and place value concepts, estimation, and organization of data. It also takes the students outside with a clearly defined task to accomplish.

2 - Wolfram Alpha. Says it author Coleen Young: This page is from the student version of my blog and has several slideshows showing the syntax for WolframAlpha including a fun show at the end on the sillier questions one can ask! I started this student version because they can just be given the link. One of my former students emailed me recently to tell me how much she was using WolframAlpha at university.

3 - New intuitive ways of learning math by Mohamed Usama. Says Mohamed, “I am a student and I love game programming. CREVO is just my virtual startup where I publish all my ideas and other news. Math Operations is a game that won local game development competition. That time, I developed this game in Flash. It was just a 48 hour competition but still idea was executed well. At the time when I was receiving my prize I announced that soon, I’ll publish it for all Android devices and here it is. I finally developed this game for all Android & Amazon Kindle Fire devices. Designed graphics (SD & HD) for tablet as well. Last week I published my new version 1.5 and its available on Google Play (Amazon is still reviewing it). I hope you people will love it. I need high support because I really want to make games for kids, education sector is what my target is.

4 - Guess my rule says its author John Golden is a story of an algebra lesson based on a simple, common social game.

5 – You Want School Reform? Brace Yourself…. submitted by Matt Wilson. Writes Matt in the post “Anybody building a house needs to start by building a foundation, but our system is teaching foundation building without ever teaching anyone what a house actually is…”

6 - Missing Angles says the author of Five Triangles is a non-trivial math problem for middle school students requires some actual thinking.

7 – An elegant solution: An algebra problem from 1798 by Dan Pearcy. Says Dan, I stumbled across this great little problem on John Cook’s blog (The Endeavour) during the weekend. The reasons that it’s so great are two-fold: (1) Most people think they’ve solved it when they have four solutions from their equation when in fact they have not considered that the equation could be written in four different ways. (2) The solutions are so elegant. Possibly because they are all based around the golden ratio.

8 - More on Microsoft Equation Editor says John Chase is a follow-up and more in-depth discussion of http://mrchasemath.wordpress.com/2012/03/15/microsoft-office-equation-editor/.

9 – Sidewalk Math: Functions. No name was supplied but its from a blog called “The Map is Not the Territory”.

10 – 9 TED talks to get your teens excited about math shared by Caroline Mukisa. A great collection.

11 - Thinking (and teaching) like a mathematician. Says Denise, “Being ‘good at math’ means much more than being able to work with numbers. It means making connections, thinking creatively, seeing familiar things in new ways, asking “Why?” and “What if?” and “Are you sure?” If we want to teach real mathematics, we teachers need to learn to think like mathematicians. We need to see math as a mental game, playing with ideas.”

12 – Tiger’s Mum presents Geometry: 2D and 3D posted at The Tiger Chronicle.

13 - Another Proof of the Sum of the First n Positive Integers and The Mathematics of the Poles shared by Guillermo Bautista. The first shows a geometric proof and the second post is a discussion on the connection among poles of the earth, the latitudes and longitudes, and the polar coordinates.

14 - Planning and Analyzing Mathematics Lessons in Lesson Study by Erlina Ronda (that’s me). This is a powerpoint presentation for researching lessons with your colleagues. Lesson study is schools-based teacher-led professional development model.

15 - The nature of math vs the nature of school math. This is my top post this month. Everybody is concerned about the great divide between math and math education.

The next MTap Carnival will be hosted in Math Mama Writes.

Thanks for including my post Sidewalk Math: Functions in this blog carnival! I thought I put my name in the submission form, but oh well! Thanks again.

Thank you for hosting the carnival! I’m looking forward to reading these posts.