Abaci (abacus)

Description:	In Ancient times, written numbers did not exist. The earliest counting device was the human hand and its fingers. Then, as larger quantities were counted, various natural items like pebbles and twigs were used to help count. Merchants who traded goods not only needed a way to count goods they bought and sold, but also to calculate the cost of those goods. The abacus, as we know it today, appeared in China around 1200 A.D. On each rod, this classic Chinese abacus has 2 beads on the upper deck and 5 on the lower deck. The abacus spread to Japan, via Korea, around 1600 A.D., but evolved to the 1 bead on the upper deck and 4 beads on the lower deck style around 1930. This style is still used and manufactured in Japan today. The Russian abacus, which is oriented horizontally, was invented in the 17th century and is still used in some parts of the country.
Source:	http://www.digitalindy.org/cdm/ref/collection/tcm/id/1486
Collection:	The Children's Museum of Indianapolis
Rights:	https://creativecommons.org/licenses/by-sa/3.0/;
Copyright:	Creative Commons (CC By-SA 3.0);
Subjects:	Abacus Mathematical instruments Counting

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