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Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 3:47 am
Hello everyone. I figured some members may find this entertaining and interesting. Arthur Benjamin does a great job here; he does miss (722)^2 and (457)^2, but he's still awesome.
Benjamin
Here are some books if you are interested in mental calculation:
Smith, Steven B. The Great Mental Calculators: The Psychology, Methods, and Lives of Calculating Prodigies Past and Present. New York: Columbia University Press, 1983.
Benjamin, Arthur and Shermer, Michael. Secrets of Mental Math: The Mathemagician's Guide to Lightning Calculation and Amazing Math Tricks. USA: Three Rivers Press, 2006.
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 3:59 am
Seen this guy's Ted talk. My only thoughts are
WITCH!!!! 
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 4:04 am
(October 31, 2016 at 3:59 am)Vic Wrote: Seen this guy's Ted talk. My only thoughts are
WITCH!!!!
Cool. You may or may not have seen this one; it was a show he did in 1985.
Benjamin
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 12:25 pm
(This post was last modified: October 31, 2016 at 12:25 pm by Fireball.)
I used to do mental math back when we had slide rules. One needs to be sure of the magnitude of the number when calculating, in order to operate the slide rule properly. After a while, it's just easier to do the math in your head. I could multiply a pair of two digit numbers faster in my head than most people could on a calculator. I haven't had a need for that in awhile, so it takes me longer to do it. Never heard of these books, but as long as I have a calculator, I'm OK. He's certainly entertaining!
If you get to thinking you’re a person of some influence, try ordering somebody else’s dog around.
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 12:38 pm
I hate doing arithmetic in my head, especially with large numbers. I prefer pen and paper all the way.
That said, I do find it impressive when someone like him can do this stuff. What I also found interesting (from a social psychology perspective) in that video is that, even when he messed up, they didn't "dare" to tell him he was wrong.
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 12:47 pm
Check out Scott Flansburg.
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
October 31, 2016 at 2:18 pm
(This post was last modified: October 31, 2016 at 2:19 pm by Kernel Sohcahtoa.)
(October 31, 2016 at 12:25 pm)Fireball Wrote: I used to do mental math back when we had slide rules. One needs to be sure of the magnitude of the number when calculating, in order to operate the slide rule properly. After a while, it's just easier to do the math in your head. I could multiply a pair of two digit numbers faster in my head than most people could on a calculator. I haven't had a need for that in awhile, so it takes me longer to do it. Never heard of these books, but as long as I have a calculator, I'm OK. He's certainly entertaining!
Cool post, Fireball. I used to be into mental calculation. In particular, I enjoyed doing big multiplications. For example, I am able (naturally with lots of practice) to multiply two distinct five digit numbers in a minute or less (I'm a bit rusty now though); however, I need to see the numbers in order to do it fast. While Benjamin uses left to right calculation and verbal mnemonics to store his intermediate calculations, I used photo mnemonics to store some of the digits I obtained via cross multiplication. If anyone is interested to learn how to multiply four or five digit numbers, just let me know and I'd be more than happy to make a video; IMO, it is a nice addition to any magician's/mathemagician's bag of tricks . With that said, I'm glad that people have enjoyed this.
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
November 1, 2016 at 1:15 am
Hello AF members. Thanks for your replies so far. Like Benjamin's finale, here's my attempt at mentally multiplying two five digit numbers. Please be warned that this is not riveting viewing; I lack Benjamin's suspense and showmanship. Hence, IMO, this will only be interesting if you like seeing people do this kind of stuff.
Mental Math
P.S. My intent is not to show off: my aim is only to have fun with this thread and post something which other members may find interesting. Thanks. Live long and prosper.
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
November 1, 2016 at 4:22 pm
Impressive! I recall that I studied Jakow Trachtenberg's book on speed multiplication when I was 11 or 12. I don't recall all the rules; that was over half a century ago.
I lived in a small town in the lower desert of southern California, and the only other entertainment in town was watching fenders rust in the wrecking yard...a slow process, in the desert. 
Trachtenberg, via wiki- https://en.wikipedia.org/wiki/Trachtenberg_system
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RE: Mental Calculation Show: Arthur Benjamin, The Mathemagician
November 1, 2016 at 4:39 pm
(This post was last modified: November 1, 2016 at 4:39 pm by Edwardo Piet.)
I can't focus on the math but your voice is awesome Kernel.
Here's another awesome voice:
https://www.youtube.com/watch?v=WNkaahnOFZQ
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