Below this crack is another group of eleven parallel lines, again divided into two sections by a line perpendicular to them but with the semi-circle 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. In the center of the tablet are a set of 5 horizontal parallel lines divided equally by a perpendicular vertical line, capped with a semi-circle at the intersection of the bottom-most horizontal line and the vertical line.īelow these lines is a wide space with a horizontal crack dividing it. It is a slab of white marble measuring 149cm in length, 75cm in width and 4.5cm thick, on which are 5 groups of markings. THE SALAMIS TABLET The oldest surviving counting board is the Salamis tablet (originally thought to be a gaming board), used by the Babylonians circa 300 B.C., discovered in 1846 on the island of Salamis. COUNTING DEVICES THROUGH THE AGES The evolution of the counting device can be divided into three ages: Ancient Times, Middle Ages, and Modern Times. The wooden boards then gave way to even more more durable materials like marble and metal (bronze) used with stone or metal markers. With the need for portable devices, wooden boards with grooves carved into the surface were then created and wooden markers (small discs) were used as place-holders. A benefit of these counting boards on tables, was that they could be moved without disturbing the calculation- the table could be picked up and carried indoors. Affluent merchants could afford small wooden tables having raised borders that were filled with sand (usually coloured blue or green). Used in outdoor markets of those times, the simplest counting board involved drawing lines in the sand with ones fingers or with a stylus, and placing pebbles between those lines as place-holders representing numbers (the spaces between the lines would represent the units 10s, 100s, etc.) two pebbles inthe 10s column would indicate 20. What did the first counting board look like? The earliest counting boards are forever lost because they were constructed of perishable materials like wood.Įducated guesses can be made about the construction of counting boards based on early writings of Plutarch and others. The person operating the abacus performs calculations in their head and uses the abacus as a physical aid to keep track of the sums, the carrys, etc. The abacus is a device, usually of wood (romans made them out of metal and they are made of plastic in modern times), having a frame that holds rods with freely-sliding beads mounted on them.īoth the abacus and the counting board are mechanical aids used for counting they are not calculators in the sense we use the word today. The counting board is a piece of wood, stone or metal with carved grooves or painted lines between which beads, pebbles or metal discs were moved. It is important to distinguish the early abacuses (or abaci) known as counting boards from the modern abaci. What is the difference between a counting board and an abacus? When the Hindu-Arabic number system came into use, abaci were adapted to use place-value counting.Ībaci evolved into electro-mechanical calculators, pocket slide-rules, electronic calculators and now abstract representations of calculators or simulations on smartphones. The abacus is one of many counting devices invented to help count large numbers. Various portable counting devices were invented to keep tallies. Merchants who traded goods needed a way to keep count (inventory) of the goods they bought and sold. Then, as even larger quantities (greater than ten fingers and toes could represent) were counted, various natural items like pebbles, sea shells and twigs were used to help keep count. The earliest counting device was the human hand and its fingers, capable of counting up to 10 things toes were also used to count in tropical cultures. It is difficult to imagine counting without numbers, but there was a time when written numbers did not exist. The abacus is one of many types of counting devices which are used to count large numbers. Abacus is a Latin word that has its origins in the Greek words abax or abakon (meaning "table" or "tablet") which in turn, possibly originated from the Semitic word abq, meaning "sand".
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