<P> During the Achaemenid Empire, around 600 BC the Persians first began to use the abacus . Under the Parthian, Sassanian and Iranian empires, scholars concentrated on exchanging knowledge and inventions with the countries around them--India, China, and the Roman Empire, when it is thought to have been exported to other countries . </P> <P> The earliest archaeological evidence for the use of the Greek abacus dates to the 5th century BC . Also Demosthenes (384 BC--322 BC) talked of the need to use pebbles for calculations too difficult for your head . A play by Alexis from the 4th century BC mentions an abacus and pebbles for accounting, and both Diogenes and Polybius mention men that sometimes stood for more and sometimes for less, like the pebbles on an abacus . The Greek abacus was a table of wood or marble, pre-set with small counters in wood or metal for mathematical calculations . This Greek abacus saw use in Achaemenid Persia, the Etruscan civilization, Ancient Rome and, until the French Revolution, the Western Christian world . </P> <P> A tablet found on the Greek island Salamis in 1846 AD (the Salamis Tablet), dates back to 300 BC, making it the oldest counting board discovered so far . It is a slab of white marble 149 cm (59 in) long, 75 cm (30 in) wide, and 4.5 cm (2 in) thick, on which are 5 groups of markings . In the center of the tablet is a set of 5 parallel lines equally divided by a vertical line, capped with a semicircle at the intersection of the bottom-most horizontal line and the single vertical line . Below these lines is a wide space with a horizontal crack dividing it . Below this crack is another group of eleven parallel lines, again divided into two sections by a line perpendicular to them, but with the semicircle at the top of the intersection; the third, sixth and ninth of these lines are marked with a cross where they intersect with the vertical line . Also from this time frame the Darius Vase was unearthed in 1851 . It was covered with pictures including a "treasurer" holding a wax tablet in one hand while manipulating counters on a table with the other . </P> <Table> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Td_colspan="2"> Abacus </Td> </Tr> <Tr> <Th> Chinese </Th> <Td> 算盤 </Td> </Tr> <Tr> <Th> Literal meaning </Th> <Td> "calculating tray" </Td> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Th_colspan="2"> (show) Transcriptions </Th> </Tr> <Tr> <Th_colspan="2"> Standard Mandarin </Th> </Tr> <Tr> <Th> Hanyu Pinyin </Th> <Td> suànpán </Td> </Tr> <Tr> <Th> IPA </Th> <Td> (swân. phǎn) </Td> </Tr> <Tr> <Th_colspan="2"> Yue: Cantonese </Th> </Tr> <Tr> <Th> Yale Romanization </Th> <Td> syun - pùhn </Td> </Tr> <Tr> <Th> IPA </Th> <Td> (sȳːnphǔːn) </Td> </Tr> <Tr> <Th> Jyutping </Th> <Td> syun - pun </Td> </Tr> <Tr> <Th_colspan="2"> Southern Min </Th> </Tr> <Tr> <Th> Hokkien POJ </Th> <Td> sǹg - pôan </Td> </Tr> <Tr> <Th> Tâi - lô </Th> <Td> sǹg - puânn </Td> </Tr> </Table> </Td> </Tr> <Tr> <Td_colspan="2"> </Td> </Tr> </Table>

Who invented the abacus when was it invented and what was it used for