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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 Roman abacus was the first portable calculating device for engineers, merchants, and presumably tax collectors.It greatly reduced the time needed to perform the basic operations of arithmetic using Roman numerals.
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]
However, the identification of the object as an abacus is a matter of some debate. [5] 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.
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]
The Sumerians' abacus consisted of a table of successive columns which delimited the successive orders of magnitude of their sexagesimal number system. [4]: 11 Its original style of usage was by lines drawn in sand with pebbles. Abaci of a more modern design are still used as calculation tools today, such as the Chinese abacus. [5]