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An abacus (pl.: abaci or abacuses), also called a counting frame, is a hand-operated calculating tool which was used from ancient times in the ancient Near East, Europe, China, and Russia, until the adoption of the Hindu–Arabic numeral system. [1] An abacus consists of a two-dimensional array of slidable beads (or similar objects). In their ...
Gottfried Wilhelm Leibniz (or Leibnitz; [a] 1 July 1646 [O.S. 21 June] – 14 November 1716) was a German polymath active as a mathematician, philosopher, scientist and diplomat who is credited, alongside Sir Isaac Newton, with the creation of calculus in addition to many other branches of mathematics, such as binary arithmetic and statistics.
The Late Roman hand abacus shown here as a reconstruction contains seven longer and seven shorter grooves used for whole number counting, the former having up to four beads in each, and the latter having just one. The rightmost two grooves were for fractional counting. The abacus was made of a metal plate where the beads ran in slots.
The first abacus pictured below (fig. 5) is decorated with simple mouldings and ornaments, common during the 12th century, in Île-de-France, Normandy, Champagne, and Burgundy regions, and from the choir of Vézelay Abbey (fig. 6). Figure 7 shows a circular abacus used at windows in the side chapels of Notre Dame de Paris. Towards the end of ...
A logical machine or logical abacus is a tool containing a set of parts that uses energy to perform formal logic operations through the use of truth tables. Early logical machines were mechanical devices that performed basic operations in Boolean logic .
Alabama: The History of a Deep South State (3rd ed. 2018; 1st ed. 1994), 816pp; the standard scholarly history online older edition; online 2018 edition; Alabama State Department of Education. History of Education in Alabama (Bulletin 1975, No. 7.O) Online free; Bridges, Edwin C. Alabama: The Making of an American State (2016) 264pp excerpt
These new surroundings hastened the development of an existing idea: an adding machine. His new job gave him the opportunity to build his prototype. Accuracy was the foundation of his work. He made his design drawings on metal plates to prevent distortion. Burroughs filed his first patent for the invention of a "calculating machine" in 1885. It ...
The counting board is the precursor of the abacus, [1] and the earliest known form of a counting device (excluding fingers and other very simple methods). Counting boards were made of stone or wood, and the counting was done on the board with beads, pebbles etc. [ 2 ] Not many boards survive because of the perishable materials used in their ...