Abacus
device · 2700 BC · Ancient world
A counting board with movable pebbles or beads.
What it is made of
- Wooden frame — has part. A frame with rods.
- Abacus beads — has part. Movable beads — the places of a number.
- Abacus rods — has part. Guides for the beads.
Principles and materials it uses
- Wood — is made of. The counting board was made of wood.
- Stone — is made of. Counting was done with pebbles — the Latin calculus.
What it is a kind of
- Computing device — is a kind of. A counting tool.
Things built in a similar way
- Hindu–Arabic numerals — works like. Positional counting with beads.