Wording of this Handout:
The abacus is a simple counting machine first used be the ancient Greeks and Romans.
The abacus consists of rows of beads stung on wires. Those on the first wire count as ones, those on the second wire count as tens, on the third wire as hundreds, and so on.
The abacus is still used in Eastern countries such as China and Japan.
The Romans sometimes used small stones as counters. They called these counters "calculi," which is where we get the word "calculate."