What is/are the history of inventor of the ABACUS??

# 1 Greek abacus

# 2 Roman abacus

# 3 Chinese abacus

# 4 Japanese abacus

# 5 Russian abacus

# 6 School abacus

# 7 Native American abaci

Origins

The origins of the abacus are disputed; many cultures are known to have used similar tools. It is known to have first existed in Mesopotamia[1][2] and China,[3] and was invented sometime between 1000 BC and 500 BC.[4] The first abacus was almost certainly based on a flat stone covered with sand or dust. Words and letters were drawn in the sand; eventually numbers were added[5] and pebbles used to aid calculations. From this, a variety of abaci were developed; the most popular were based on the bi-quinary system, using a combination of two bases (base-2 and base-5) to represent decimal numbers. But the earliest abaci used first in Mesopotamia and later by scribes in Egypt and Greece used sexagesimal numbers represented with factors of 5, 2, 3, and 2 for each digit. See http://home.comcast.net/~sks23cu/SalamisTablet/ for description and how to use.

The use of the word abacus dates from before 1387, when a Middle English work borrowed the word from Latin to describe a sandboard abacus. The Latin word came from abakos, the Greek genitive form of abax (“calculating-table”). Because abax also had the sense of “table sprinkled with sand or dust, used for drawing geometric figures”, some linguists speculate that the Greek word may be derived from a Semitic root, ābāq, the Hebrew word for “dust”. Though details of the transmission are obscure, it may also be derived from the Phoenician word abak, meaning “sand”. The plural of abacus is often subject to heated debate. The equivocal American dictionary cites the plural as abaci with reference to similar usage with the words Cactus and Fungus. However the equivocal British dictionary cites the plural as abacuses due to the word’s Arabic origin. [6]

p.s. that thing is HARD to use….i have one and still dont know how to use it