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An adapted abacus, invented by Tim Cranmer, and called a Cranmer abacus is commonly used by visually impaired users. A piece of soft fabric or rubber is placed behind the beads, keeping them in place while the users manipulate them.
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.
Abacus – The Aztec and Maya of Mesoamerica performed arithmetic operations using an abacus. It served as a more accurate and faster alternative to a written solution or relying on memory. Archaeologists have recorded the Mesoamerican abacus, or Nepohualtzintzin, as being present in Mesoamerica from at least between 900 and 1000 CE. [1]
The abacus was early used for arithmetic tasks. What we now call the Roman abacus was used in Babylonia as early as c. 2700 –2300 BC. Since then, many other forms of reckoning boards or tables have been invented.
Zhusuan was an abacus invented in China at the end of the 2nd century CE and reached its peak during the period from the 13th to the 16th century CE. In the 13th century, Guo Shoujing (郭守敬) used Zhusuan to calculate the length of each orbital year and found it to be 365.2425 days.
In c. 1050 –771 BC, the south-pointing chariot was invented in ancient China. It was the first known geared mechanism to use a differential gear, which was later used in analog computers. The Chinese also invented a more sophisticated abacus from around the 2nd century BC known as the Chinese abacus. [citation needed]
Number 0, invented by the Maya or possibly the Olmec. An illustration of the Pre-Columbian abacus: the Nepohualtzintzin. The ancient Mexicans also developed complex arithmetic functions and operations such as additions, subtractions, divisions, and multiplications.
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 ...