Search results
Results from the WOW.Com Content Network
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]
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.
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.
A pinwheel calculator is a class of mechanical calculator described as early as 1685, and popular in the 19th and 20th century, calculating via wheels whose number of teeth were adjustable. These wheels, also called pinwheels, could be set by using a side lever which could expose anywhere from 0 to 9 teeth, and therefore when coupled to a ...
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 ...
Friden Calculator Friden Flexowriter. In 1957, Friden purchased the Commercial Controls Corporation of Rochester, New York.This gave them the Flexowriter teleprinter, an electric typewriter capable of being used as part of unit record equipment developed in World War II for the Department of the Navy to automatically type "regret to inform you" letters to the survivors of fallen servicemen ...
The Comptometer was the first commercially successful key-driven mechanical calculator, patented in the United States by Dorr Felt in 1887.. A key-driven calculator is extremely fast because each key adds or subtracts its value to the accumulator as soon as it is pressed and a skilled operator can enter all of the digits of a number simultaneously, using as many fingers as required, making ...
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 ...