If you are refering to Chinese abacus their earliest rudimentary design of abacus has 1/4 rod beads (quite similar to the later Japanese soroban abacus). Various other types of abacus design were also seen afterwards, but the advance type of 2/5 rod beads became standard and classic. Afterwards, the basic 1/5 rod beads particularly became the type of basic design. The Roman abacus may be not connected to the Chinese abacus.
China invented the abacus .
How did the abacus occur?
An Abacus has beads and strings.
The Chinese abacus
ABACUS
Other than the human brain, the Abacus
it is the abacus. :D :D :D i got is dummies
The abacus II!
the Chinese invented the abacus
the invenor of the abacus is the invenor of me
Abacus was invented by the Chinesethe abacus was also known as the first computer