I think is Jeonghee Lee. And you, what person do you think is the best?

# Who is the best mental calculator?

Shakuntala Devi is to me the best mental calculator of all time. Her feat of multiplying a 13 digit number with another 13 digit number in 28 seconds was so far ahead of the other mental calculators during that time that some people just couldnâ€™t believe she actually did it. That feat is still impressive today and if she were still alive, she would be considered top 20 best mental calculators in the world even at an old age.

She was a prodigy as a child and her talents never faded. I think that Devi in her prime > any other mental calculator ever. I want to believe that the reason Devi was so extraordinary is because she was already gifted with numbers before she ever used techniques and methods to increase her talents but unfortunately we will never know.

If you donâ€™t mind it would be nice to create a list not just of the best but also of famous and or useful calculators.

I am a great fan of Art Benjaminâ€™s teaching skills.

Swami Bharati Krishna Tirtha for his books and establishing the idea of vedic mathematics.

Jakow Trachtenberg for his creation of the trachtenberg system.

I do not know who brought modern anzan out but it is stunningly effective by those that have mastered it.

I tend to be a fan of the europeanâ€™s such as Euler and using algebra and the properties of numbers. Euler was considered a prodigious mental calculator in his time.

I remember that there is also a finger couting method, korean, I believe called chisonbop that is quite valuable.

I donâ€™t know how representative the â€śMental Calculation World Cupâ€ť results are as it seems unlike that many go but http://www.recordholders.org/en/events/worldcup/2018/results.html

When it comes to television type things much of the presentation of mental calculation is often for show as the audience doesnâ€™t really care about either the process or the result they just like to see video of circus freaks. This makes those represented as savant very difficult to judge pragmatically.

If we want to look for future young mathematicians the International Mathematical Olympiad seems to be a good place to watch. Seems to be a reasonable correlation between medalists and fields medal winners. We could probably find a number of world class mental calculators in that list. https://www.imo-official.org/ Zhuo Qun (Alex) Song looks like a possible â€¦ https://www.imo-official.org/participant_r.aspx?id=19624

What about Jacques Inaudi?

I read many times ago he was the best calculator ever.

Another interesting on is Rudiger Gamm in this video he discussed his approach and methods

Interesting that he says that powers of 3 digit numbers would be challenging for him but 2 digit numbers to high powers are not. His description seems very much based on memory.

Sorry, my English listening is not so good.

However is Mr Gamm more a mnemonist than a human calculator?

In my calculations I work with brute-force approach, so is the technique I more enjoy being applied by human calculators.

Calculators and mathematicians are distinct. Calculation is all about accurate and high speed manipulation of the numbers. They are usually not much concerned with proving their methods or with the underlying math, the focus is on technique. Rudiger Gamm once remarked that he could calculate sine values but didnâ€™t know how they are used. Until you and I showed up here, there had been very little discussion of the underlying math.

Among mathematicians and physicists, strong mental calculators, like Euler and Feynman do appear but itâ€™s not a requirement and it never won them any special standing. When I worked with a community of physicists and engineers, people who work with numbers all the time, I was the fastest with the numbers - that is to say quick ballpark estimates. On this forum, I donâ€™t even rate.

Iâ€™ve even seen Number Theorists stumble. Tried to square 19 in his head. Had to do it with pencil and paper.

I love Wim Klein as seen here:

One of the things I love about him is that he is Dutch.

While working for CERN, he speaks French. However; when calculating he mumbles Dutch. Sometimes even swears if things get difficult for him.

Fantastic to hear!

Zacharias Dase was able to multiply two 100 digit numbers in 8 hours 45 minutes!

Source: http://www-groups.dcs.st-and.ac.uk/history/HistTopics/Mental_arithmetic.html

Look here http://www-groups.dcs.st-and.ac.uk/history/HistTopics/Mental_arithmetic.html about Zacharias Dase and George Parker Bidder.