-
habacus
The abacus (plural abaci or abacuses), also called a counting frame, is a calculating tool that was in use in the ancient Near East, Europe, China, and Russia, centuries before the adoption of the written Arabic numeral system.[1] The exact origin of the abacus is still unknown. The abacus essentially consists of a number of rows of movable beads or other objects, which represent digits. One of two numbers is set up, and the beads are manipulated -
pascalina
Pascal's calculator (also known as the arithmetic machine or Pascaline) is a mechanical calculator invented by Blaise Pascal in the mid 17th century. 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] He designed the machine to add and subtract two numbers directly and to perform multiplication and division through repeated addition or subtraction. -
neperian habacus
The abacus consists of a board with a flange on which the Neperian rods will be placed to perform multiplication or division operations. The board has its left edge divided into 9 squares on which the numbers 1 to 9 are written. Neperian rods are strips of wood, metal, or thick cardboard. The front face is divided into 9 squares, except the top one, divided into two halves by a diagonal line.
