China invented the abacus .
disadvantage of abacus
who discover abacus
The Chinese abacus
An Abacus has beads and strings.
How did the abacus occur?
The First appearance of an abacus was in Sumeria around 2700 to 2300 BC.
the Chinese invented the abacus
The abacus II!
the invenor of the abacus is the invenor of me
the history about the abacus is that 3000 years ago the chinese invented the abacus. The abacus was made of wood parrelel rod and beads.