OT revolution in the brain
- Odd roots of power numbers can be extracted with tricks (I mean, without doing the actual
computation). You don't need a marvellous speed, only a pretty good memory.
I do third (up to 10^6, easy to go further) and fifth roots (up to 10^10, easy to go
further) instantaneously to entertain my friends.
No magic here. I am a friend of Alberto Coto, Record Guiness of mental speed in basic
arithmetic, and that's really magic. You can not use tricks to add at his marvellous
----- Original Message -----
From: "Alexis Lemaire" <alexislemaire2000@...>
Sent: Sunday, April 24, 2005 11:07 AM
Subject: [PrimeNumbers] revolution in the brain
I am Alexis Lemaire from France, the world recordholder for the
extraction of the 13th root of a 200-digit number.
I won the title 4 days after the Pope's death.
There are several articles published everywhere in the world about
the 13th root record broken in France
(In English, there are also the Times, the press agencies AFP,
Reuters and AP)
The last one is the following
For amazing and revolutionary ideas about the brain, the memory, and
even the Apocalypse
Another article found in the Telegraph, a British newspaper:
(I've discussed with the correspondant recently)
Do you know what the 13th root of
By Henry Samuel in Paris
A French computer science student has stunned the world of
mathematics by working out the 13th root of a 200-digit number in
his head in under nine minutes.
By arriving at the 16-digit answer from 390 trillion possibilities,
Alexis Lemaire, 24, pulled off the most difficult feat of mental
arithmetic ever attempted.
Mr Lemaire was presented with a random 200-digit sprawl on a
computer and asked to work out its 13th root. The answer, multiplied
by itself 13 times, would match the figure on the screen.
Thirteenth roots are a yardstick in mental arithmetic, because 13 is
a prime number whose roots cannot be obtained by combining those of
Yet Mr Lemaire appeared only mildly satisfied by his feat. At his
next record attempt, he said, his brain would work even faster. "As
this was my first attempt, I was cautious." On June 3, he will try
to find the right answer in less than three minutes. In a few
months, he believes that he will break the one-minute barrier. "If I
do that, without being pretentious, it will probably be the best
piece of mental calculation ever," he said.
Mr Lemaire has spent four years developing a secret matrix technique
in which he memorises thousands of inter-linked tables of numbers to
aid his calculations. "It's just like learning your times tables
really," he said. "But the numbers are bigger."
He subjects his brain to intensive training, with three hours of
mind games a day. Like all mental arithmetic champions, he can
readily move information from his short-term memory and anchor it in
his long-term memory.
In December, he took only 3.62 seconds to find the 13th root of a
100-digit number, obliterating the previous record of 13.55 seconds
held by a German, Gert Mittring.
Mr Lemaire now wants to find practical uses for his skill: learning
40 languages simultaneously or becoming a "card sharp" to clean up
"It's all about thinking visually," he said. "I have a map or matrix
in my head of thousands of tables that I have learned side by side.
I can scroll through them and pick out the numbers I need.
"Above all, you need to link the different items. If you forget
something, you have lost the link to that memory, but if you have
created several links, even if one breaks you can choose another
route," he said.
Scientists at Caen University who studied the brain activity of a
fellow prodigy, Rudiger Gamm, from Germany, concluded that such
arithmeticians coached their brains to behave differently.
"Training has modified the brain's wiring and the size of cerebral
areas," said Bernard Mazoyer, who runs a brain imaging centre at
Caen. He warned that they might lose the knack of communicating with
other people if they focused too hard on maths.
"There is a risk of suffering a form of adult autism during such
intensive training because of the acts of sheer concentration
involved," he said.
For anyone seeking to challenge his record, Mr Lemaire has an
invaluable tip: all answers begin with the number 2. And the answer
to our 200-digit headline question? 2391481494636373.
Alexis Lemaire, calculating prodigy of amazement - 13th Root.com
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