Albert Einstein’s birthday was a couple of weeks ago, but today we have a belated celebration. MinutePhysics has finally finished its series on Einstein’s “wonder year” discoveries of 1905. In the last video, we began learning about the Special Theory of Relativity. This time, we find out how that theory leads to the most famous equation in the world…

## Math Blog Carnival Update

*photo by jaycoxfilm via flickr*

Blog renovations are nearly complete, including an overhaul to the ** Math Teachers at Play** blog carnival. The MTaP carnival is a monthly collection of tips, tidbits, games, and activities for students and teachers of preschool through pre-college mathematics. It’s not just for “math teachers”! We welcome entries from parents, students, teachers, homeschoolers, and just plain folks. If you like to learn new things and play around with ideas, you are sure to find something of interest.

We will be publishing MTaP during the second full (Monday-Friday) week of each month, with the exact day of publication during that week left to the host blogger’s discretion. For more information, check out:

- MTaP Blog Carnival Information Page
- MTaP Submission Form (to enter your blog post in the carnival)
- Browse all the past editions of the
*Math Teachers at Play*blog carnival

## 0.999… = 1 via Vi Hart

### And For Balance

### Mind Blown Yet?

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## MTaP Blog Carnival Submission Form

*Photo by Bob Jagendorf via flickr.*

The blog carnival website has been unreliable for months now, and it’s high time we came up with another way for you to submit your posts to the *Math Teachers at Play* blog carnival. So when I saw the snazzy new *Carnival of Mathematics* submission form, I knew I had to learn to use Google Docs.

## Happy Birthday, Einstein (Part 3)

In 1905, when he was 26 years old, Albert Einstein rocked the scientific world with a series of papers that changed our understanding of the nature of the universe. At MinutePhysics, the celebration continues:

## More Einstein Videos

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## Used Book Price Shock

Someone mentioned one of my old books on the Living Math forum, which made me curious how the used copies were doing at Amazon.com. These are simple little books, 100 loose pages comb-bound together. I have seen ridiculous prices before, but this one takes the cake.

Thankfully, there are a few used book dealers with more sense, or at least with more reasonable computer-automated pricing routines.

I am still at work revising (and greatly expanding) the old books so I can publish new editions. If you haven’t voted yet in my “What Do You Want from a Math Book?” survey, I’d love to hear your opinion!

Want to help your kids learn math? Claim your free 24-page problem-solving booklet, and sign up to hear about new books, revisions, and sales or other promotions.