'Mathlete' breaks calculation record - 13th root of a random 200 digit number

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dyn2nvu

Senior member
Feb 8, 2004
631
1
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After a great deal of brow-furrowing and lip-chewing, he calculated the answer to be 2,407,899,893,032,210.

Alexis Lemaire, 27, yesterday broke the world speed record for calculating the 13th root - the number that must be multiplied 13 times by itself to reach a solution - of a randomly generated 200 digit number.

http://www.telegraph.co.uk/ear.../12/11/scimaths111.xml
 
Epic Fail

Epic Fail

Diamond Member
May 10, 2005
6,252
2
0
I thought the article has a typo with root instead of power, but it is root. :Q
 
F

Farang

Lifer
Jul 7, 2003
10,913
3
0
Wow. For reference, a 200-digit number:

384,958,473,838,495,847,383,849,584,738,384,958,473,838,495,847,383,849,584,738,384,958,473,838,495,847,383,849,584,738,384,958,473,838,495,847,383,849,584,738,384,958,473,838,495,847,383,849,584,738,384,958,473,838,49,584,738,384,958,473,838,495,847,383,849,584,738
 
OUCaptain

OUCaptain

Golden Member
Nov 21, 2007
1,522
0
0
Yeah, and he did it in 72 seconds! I've seen this guy before on Discovery channel. His math skills put rain man to shame.
 
mobobuff

mobobuff

Lifer
Apr 5, 2004
11,099
1
81
Christ how can you even comprehend such a number in a lifetime, let alone 72 seconds?

What do you do with witches?

BURN THEM!

And what do you burn apart from witches?

MORE WITCHES!
Shhh... Wood!?

So... why do witches burn?

...

Cause they're made of wood?

Good! So... how do we tell whether he is made of wood?

Build a bridge out of him!

Ah but can you not also make bridges out of stone?

Oh yeah, yeah...

Ah does wood sink in water?

No, no! It floats! It floats!
Throw him into the harbor!

What also floats in water?

Bread! Apples! Ah, very small rocks! Cider! A grape gravy, cherries, mud! Churches, churches! Lead! Lead!

A duck...
 
IEC

IEC

Elite Member
Super Moderator
Jun 10, 2004
14,600
6,084
136
And I thought I did some ridiculous things with my number-sense skills back in the day... that surpasses all of the "tricks" I know combined...
 
1prophet

1prophet

Diamond Member
Aug 17, 2005
5,313
534
126
He has natural ability but he also works very hard at it.

He trains for around four hours per day, practising calculations and memorising thousands of tables of numbers and multiplications.
Click to expand...





Alexis Lemaire's tips for training your brain
Last Updated: 8:01pm GMT 11/12/2007



To improve memory, Alexis Lemaire recommends spending time before bed recalling the events of the day.

Once you have perfected this, do the same for the previous day.

Doing crosswords and reading will help improve language skills, he says.

To improve mental arithmetic, he suggests simply doing harder and harder sums with increasing speed.

But it is important not to work too hard.

The brain will not perform to its full capacity when you are tired or stressed, he says.

A number of computer-based games are available to improve mental capabilities.

Prof Kawashima's Brain Training, released last year on the Nintendo DS console, involves maths, memory and reading tests.

It is designed to increase the delivery of oxygen, blood and amino acids to the brain.

Research has also suggested that elderly people who socialise more are significantly less likely to develop Alzheimer's disease.

A separate study in the New England Journal Of Medicine has claimed that doing number puzzles such as sudoku at least four times a week can reduce the risk of dementia by almost 50 per cent.

A diet rich in omega-3, found in oily fish, flaxseed and walnuts, as well as plenty of fruit and vegetables, is thought to keep the brain sharp and improve mental reaction times.

Flavonols, found in dark chocolate and some cocoa, can also boost blood flow in the brain and reduce the risk of dementia, scientists believe.
Click to expand...





 
S

steppinthrax

Diamond Member
Jul 17, 2006
3,990
6
81
I you read the article it mentions "Alexis Lemaire trains for around four hours per day, practising calculations and memorising thousands of tables of numbers" There are a lot of patterns that are related to each other when doing calculations. A good example is multiplying by 9. In grade school many were taught when doing multiplication facts when multiplying by 9 the first digit in the answer is always one less than the number other than 9.

Example

9 x 2 = [1]8
9 x 3 = [2]7
9 x 4 = [3]6.

This is a very simple relationship but there are much much more complicated relationships when making complicated calculations. So in other words if you memorize most if not all of those relationships and find new patterns out yourself you can effectivley work out large numbers. So I highly doubt he calculated this from scratch. He looked at the digits and could deduct relationships of what the root could be......
 
Born2bwire

Born2bwire

Diamond Member
Oct 28, 2005
9,840
6
71
Originally posted by: steppinthrax
I you read the article it mentions "Alexis Lemaire trains for around four hours per day, practising calculations and memorising thousands of tables of numbers" There are a lot of patterns that are related to each other when doing calculations. A good example is multiplying by 9. In grade school many were taught when doing multiplication facts when multiplying by 9 the first digit in the answer is always one less than the number other than 9.

Example

9 x 2 = [1]8
9 x 3 = [2]7
9 x 4 = [3]6.

This is a very simple relationship but there are much much more complicated relationships when making complicated calculations. So in other words if you memorize most if not all of those relationships and find new patterns out yourself you can effectivley work out large numbers. So I highly doubt he calculated this from scratch. He looked at the digits and could deduct relationships of what the root could be......
Click to expand...

Another one is calculating the square of numbers around 50. You take 2500, subtract a 100 times the difference between 50 and the number. Then you just add a correction that is equal to the square of the difference.

45: 2500-500+25 = 2025
57: 2500+700+49 = 3249

And so on. It's an easy relationship that you can derive from taking the square of (50-a) and stuff like that. It comes out: (50-a)^2 = 50^2-100*a+a^2 and 50 just happens to be an easy number to remember.
 
T

Turin39789

Lifer
Nov 21, 2000
12,218
8
81
Yea, but can he sort out the chopped up wiring on a 30 year old motorcycle? Cause I don't want to do it, and I'd appreciate it if someone would.
 
D

duragezic

Lifer
Oct 11, 1999
11,234
4
81
Wow!

The 200 digit one is good, but the 100 digit one it mentioned seems just as impressive. How in the hell it is ever possible to calculate the 13th root of a 100 digit number in 3.6 seconds? You couldn't even look at all 100 digits in that time.

Does he do this all in his head?? How can he even remember all the digits?
 
S

Saint Michael

Golden Member
Aug 4, 2007
1,877
1
0
Originally posted by: jae215
how many 100 digit numbers when calculated to the 13th root result in integers
Click to expand...

Many. Try it for yourself, type a random 100-digit number into Google with ^(1/13).

Like:

203487023760239760234^(1/13)


But with 100 digits obviously.
 
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