Mathemagician

While looking for interesting math videos, I stumbled up this video from the TED Talks website:
http://www.ted.com/talks/arthur_benjamin_does_mathemagic

I found it to be incredibly entertaining, and I think it could be awesome to show to students to get them excited about math. Basically, Arthur Benjamin completes ridiculous multiplication questions and squares numbers that seem like they would be impossible to do without a calculator. By the end, he squares a number that is 5 digits long, resulting in an answer that is 10 digits long, which most calculators can't even do. He reveals how he does the problem, as he breaks it down into smaller steps, but it is still incredibly impressive that he can complete the steps, as they are still quite difficult, and it seems like it would be very difficult to remember the answers from each step, since he doesn't write anything down.

When in my undergrad (Human Kinetics), I learned a little bit about this when talking about savants. It turns out some people have pretended to be savants by actually using strategies like this to do incredible calculations. There are many people in the world who can do such calculations, and if my memory serves me right, there are actually competitions for this sort of thing.

Another trick he did was figuring out what day of the week someone was born on by knowing the year, month, and day. This is also a math problem that he solves in his head, as there is an equation for this as well. It takes into account the leap year every 4th year, and even the years when there is an extra leap year. As long as you know the formula, and can do the math, anybody can figure out what day of the week it was on a particular day.

Another interesting thing that occurred in the video was when he used words to recall numbers. This is a strategy used by a lot of people who have incredible memories. It is difficult to remember a 6 digit number, but if you change it into a word, you only have to remember the word, which will help you recall the number. It is a bit confusing to understand, as I still don't know how exactly a 6 digit number relates to a word so that he can use them interchangeably, but it is common practice not only in remembering math problems, but in remembering anything. I believe it is called chunking, where you take large amount of data (i.e. a large number) and change it into a small amount of data (i.e. a word), so that you can recall more data at once (i.e. several words instead of several large numbers).