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The stepped reckoner or Leibniz calculator was a mechanical calculator invented by the German mathematician Gottfried Wilhelm Leibniz (started in 1673, when he presented a wooden model to the Royal Society of London [2] and completed in 1694). [1]
Scott Flansburg (born December 28, 1963) is an American dubbed "The Human Calculator" and listed in the Guinness Book of World Records for speed of mental calculation.He is the annual host and ambassador for The National Counting Bee, a math educator, and media personality.
Pascaline (also known as the arithmetic machine or Pascal's calculator) is a mechanical calculator invented by Blaise Pascal in 1642. Pascal was led to develop a calculator by the laborious arithmetical calculations required by his father's work as the supervisor of taxes in Rouen . [ 2 ]
Friden made a calculator that also provided square roots, basically by doing division, but with added mechanism that automatically incremented the number in the keyboard in a systematic fashion. The last of the mechanical calculators were likely to have short-cut multiplication, and some ten-key, serial-entry types had decimal-point keys.
After Odhner's death, in 1905, his sons Alexander and Georg and son-in-law Karl Siewert continued the production [3] and about 23,000 calculators were made until the factory was nationalized during the Russian revolution and was forced to close down in 1918. This makes the Brunsviga arithmometer, with its 1892 start, the longest-lasting Odhner ...
Made in Japan, this was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the Mostek MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures 4.9 by 2.8 by 0.9 inches ...
Shakuntala Devi (4 November 1929 – 21 April 2013) was an Indian mental calculator, astrologer, and writer, popularly known as the "Human Computer".Her talent earned her a place in the 1982 edition of The Guinness Book of World Records.
The Curta was conceived by Curt Herzstark in the 1930s in Vienna, Austria.By 1938, he had filed a key patent, covering his complemented stepped drum. [3] [4] This single drum replaced the multiple drums, typically around 10 or so, of contemporary calculators, and it enabled not only addition, but subtraction through nines complement math, essentially subtracting by adding.