Puneet Varma (Editor)

Mental calculator

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Mental calculators are people with a prodigious ability in some area of mental calculation, such as multiplying large numbers or factoring large numbers.


Mental calculators were in great demand in research centers such as CERN before the advent of modern electronic calculators and computers. See, for instance, Steven B. Smith's 1983 book The Great Mental Calculators.

The world's best mental calculators are invited every two years to compete for the Mental Calculation World Cup. On September 25, 2016, 27-year old Yuki Kimura of Japan, succeeded 13-year-old Granth Thakkar of India, as the current world champion. (2016-2018). Yuki Kimura is the 2nd Japanese person to win the Cup, after Naofumi Ogasawara won it in 2012.

In 2005 a group of researchers led by Michael W. O'Boyle, an American psychologist previously working in Australia and now at Texas Tech University, has used MRI scanning of blood flow during mental operation in mathematical prodigies. These math prodigies have shown increases in blood flow to parts of the brain responsible for mathematical operations during a mental rotation task that are greater than the typical increases.

Mental calculators from history

  • Aitken, Alexander Craig
  • Ampère, André-Marie
  • Benjamin, Arthur, a “mathemagician”
  • Bidder, George Parker
  • Buxton, Jedediah
  • Colburn, Zerah
  • Dase, Johann Zacharias
  • Deshong, Peter M.
  • De Grote, Herbert
  • Devi, Shakuntala
  • Diamandi, Pericles
  • Dysart, Willis (a.k.a. Willie the Wizard)
  • Eberstark, Hans
  • Euler, Leonhard
  • Finkelstein, Salo
  • Fuller, Thomas
  • Gauss, Carl Friedrich
  • Griffith, Arthur F.
  • Hamilton, William Rowan
  • Inaudi, Jacques
  • Klein, Wim (a.k.a. Willem Klein)
  • McCartney, Daniel
  • Neumann, John von
  • Ramanujan, Srinivasa
  • Riemann, Bernhard
  • Ruckle, Gottfried
  • Safford, Truman Henry
  • Shelushkov, Igor
  • Wallis, John
  • Dune

    In Frank Herbert's novel Dune, specially trained mental calculators known as Mentats have replaced mechanical computers completely. Several important supporting characters in the novel, namely Piter De Vries and Thufir Hawat, are Mentats. Paul Atreides was originally trained as one without his knowledge. However, these Mentats do not specialize in mathematical calculations, but in total recall of many different kinds of data. For example, Thufir Hawat is able to recite various details of a mining operation, including the number of various pieces of equipment, the people to work them, the profits and costs involved, etc. In the novel he is never depicted as doing actual academic mathematical calculations. Mentats were valued for their capacity as humans to store data, because computers and "thinking machines" are outlawed.


    In Roald Dahl's novel Matilda, the lead character is portrayed having exceptional mathematical skills as she computes her father's profit without the need for paper computations. During class (she is a first-year elementary school student), she does large-number multiplication problems in her head almost instantly.


    Andrew Jackson "Slipstick" Libby is a calculating prodigy in Robert A. Heinlein's story Methuselah's Children.

    In the USA Network legal drama Suits, the main character, Mike Ross, is asked to multiply considerably large numbers in his head to impress two girls, and does so subsequently.

    In Haruki Murakami's novel Hard-Boiled Wonderland and the End of the World, a class of mental calculators known as Calcutecs perform cryptography in a sealed-off portion of their brains, the results of which they are unable to access from their normal waking consciousness.

    In the Fox television show Malcolm in the Middle, Malcolm Wilkerson displays astounding feats of automatic mental calculation, which causes him to fear his family will see him as a "freak," and causes his brother to ask, "Is Malcolm a robot?"

    In the 1991 movie Little Man Tate, Fred Tate in the audience blurts out the answer during a mental calculation contest.

    In the 1997 sci-fi thriller Cube, one of the prisoners, Kazan, appears to be mentally disabled but is revealed later in the film to be an autistic savant, who is able to calculate prime factors in his head.

    In 1998 Darren Aronofsky's film Pi, Maximillian Cohen is asked a few times by a young child with a calculator to do large multiplications and divisions in his head, to which he promptly answers.

    In 1998 film Mercury Rising, a 9-year-old autistic savant with prodigious math abilities cracks a top secret government code.

    In the 2006 film Stranger than Fiction, the main character, Harold Crick, is able to perform rapid arithmetic at the request of his co-workers.

    In the 2009 Japanese animated film Summer Wars, the main character, mathematical genius Kenji Koiso, is able to mentally break purely mathematical encryption codes generated by the OZ virtual world's security system. He can also mentally calculate the day of the week a person was born based on their birthday.

    In another Fox television show Fringe. the third episode of the third season Olivia and her fellow Fringe Division members encounter an individual with severe cognitive impairment who has been given experimental nootropics and as a result has become a mathematical genius. The individual is able to calculate hundreds of equations simultaneously which he uses to manipulate to his advantage to avoid being returned to his original state of cognitive impairment.

    In the 2012 film Safe, a little girl, math genius, is kidnapped to be used by the Chinese Triad.

    In the 2014 sc fi novel Double Bill by S. Ayoade, Devi Singh, a mental calculator is one of the 70 lucky children who wins a trip to the moon.

    In the 2016 film The Accountant, a high-functioning autistic tracks insider financial deceptions for numerous criminal organisations.

    Champion mental calculators

    Every two years the world's best mental calculators are invited to participate in The Mental Calculation World Cup, an international competition that attempts to find the world's best mental calculator, and also the best at specific types of mental calculation, such as multiplication or calendar reckoning. The top three final placings from each of the world cups that have been staged to date are shown below.

    Seventh Mental Calculation World Cup (Bielefeld, 2016)

    The Mind Sports Olympiad has staged an annual world championships since 1998.

    MSO mental calculation gold medal winners

    The Mind Sports Organisation recognizes three International Grandmasters of Mental Calculation: Robert Fountain (1999), George Lane (2001) and Gert Mittring (2005), and one International Master, Andy Robertshaw (2008).


    Mental calculator Wikipedia