Good morning, everybody! This month's edition of Math Teachers at Play is edition number . Also known as edition number . Or edition or edition ... depending on your interpretation, of course!

First, I'll talk about some tacky facts about , then we'll get this carnival started, shall we?

Alrighty, so... did you know that is a happy number? That's right, it's not unhappy, it quite likes the way it is. Quite like pandas - they're happy too (and there's even a page with (wait for it...)) sixty-eight interesting facts about pandas! Teeheehee - isn't fascinating?

Anyway, back to the happy stuff - here's an interesting fact. There's certain numbers that exist that are 'happy' numbers. This is because the sum of the square of their digits is equal to . So, for , the two digits are and .

Adding the squares, we're given , which equates to . Adding the square of each of the digits makes , which is happy!

Can you find some more happy numbers? I'll give you a hint - the first one is 1. š

Anyway, back to the carnival. This carnival features 11 articles - smaller than last time, but still just as awesome and creative as ever, š

### Holiday Activities

As Halloween has only just passed, I can't help but mention Lucy's wonderful Math Activity Thursday. In this special Halloween edition, she tackles the wonders of counting - with the deliciousness of candy corn. Yum!

If you're looking for a slightly less sugary option, why not try Jennifer's great article, 'Measuring with Apples'? It's a fascinating activity about non-standard measurement - and quite interesting, too.

Speaking of holidays, here's one of Ian VanderSchee's 'Rational Expressions' - published just before the new year, he explores the volume of cylinders with his family.

### Exploration and Explanation

This month, Sue VanHattum tackles a tricky historical question - What is Calculus? In Part One, she tackles the basics - with only a few words, some graphs and loaves of bread. Quite an intriguing discussion, if I do say so myself.

In the meantime, Maria Miller decides to crack open a discussion on our brains - a rather interesting discussion about brain growth, she delves into the potential of students in her article 'Brain growth and the value of mistakes'.

Finally, Liz explores the power of defiance (and the Sun) in her article - When Defiance Turns into an Experiment.

### Fun and Games

In this edition, Julie shows us the wonders of a new board game in 'Sumoku - Addition and Division Game'. It's quite delightful, š

Meanwhile, Muhammad explores colour patterns in 'Let's Play Math - Colourful Necklace.' There's a fascinating little app linked to it, with some great activities to try out.

### Activities and Worksheets

This month, Margo shows us ways to calculate area with the worksheet 'Nailing Down Area'. Can you nail down the areas?

Over at Let's Play Math, Denise shows us a challenge in logic in the activity, 'The Centauri Challenge'.

Finally, I'd like to share the activity that delayed this post by two days, an online quiz about BODMAS. This carnival was meant to go up on Friday, but in the space of five minutes, two hundred people tried the quiz - and it locked me out of the blog for thirty-six hours. I'd like to extend my apologies to all of the articles who were affected - I've adjusted my security settings, so they should be OK next time, haha!

Thank you to everyone who has taken the time to read this issue. Go on, explore the articles, chat with bloggers - get engaged with MTaP! š

As always, make sure you check out the MTaP and Carnival of Mathematics pages - CoM #104 is up now at Math-Frolic, and MTaP #69 will be held next month at Kids Math Teacher. Make sure to get involved! š

Anyway, that's all from me. See you next time!