How does an abacus work?

The ancient calculators that made complex sums simple

Before the invention of the written Hindu-Arabic numerical system that is still used worldwide today, ancient mathematicians performed complex calculations using an abacus. The device is thought to have evolved from the system of columns and markers used on Babylonian counting boards around 300 BCE, but it first appeared as it does today in China around 1200 CE.

The simple counting tool features a series of beads that can be moved up or down wires to represent numbers that are too large to be counted on the human hand. These days they have mostly been rendered obsolete by digital calculators, but they are still used by some shopkeepers in Asia to calculate each customer’s bill, as well as by the visually impaired.

Ancient arithmetic

Learn how to count using an abacus


This article was originally published in How It Works issue 102, written by Jo Stass 

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