Early counting board / abacus
Tablero de cálculo con fichas (ábaco temprano)
- Date
- c. 2400 BCE · confidence low
- Place
- Sumer and Babylon, Iraq
- Credited to
- Sumerians and Babylonians (inferred)
- Field
- Knowledge & symbols
⚠️ Disputed: the sources disagree.
What it is
Surface with columns on which pebbles or counters are placed to add and subtract in base 60. It is the first mechanical aid to calculation, inferred from texts and from the Sumerian word for 'counting board'.
No Bronze Age abacus survives; its existence is inferred from calculation errors on tablets and textual mentions. Date and place are very uncertain.
What it led to
- Fast calculation independent of writing, accessible to non-literate merchants
- A separation between calculation (ephemeral) and record-keeping (permanent)
- A tradition of computing instruments leading to the Roman and Chinese abacus and the calculator
Built on
- Clay accounting tokensc. 8000 BCE
- Sexagesimal number systemc. 3000 BCE
- Clay accounting tokens
- Sexagesimal system
Made possible
- Negative numbers and sign rulesc. 100 BCE
- Zero as a number (India)628
- Chinese abacus (suanpan)c. 1371-1592
- Greek and Roman abacus
- Chinese suanpan