# WHAT IS ABACUS?

Do you know what the abacus is? Mathematics, like all other sciences, has evolved over several millennia. Each period in history was important and contributed to the way we know it. Among the various primitive tools that were developed, there is no doubt that the abacus has an important place in history.

The first mathematical calculations were done “on the fingers”, however, as the numbers got bigger, it was necessary to develop a more effective tool. The abacus is considered the oldest calculator created by humans.

It is an instrument used for mathematical calculations created around 5,000 years ago, where it is not known for sure who was responsible for the invention. Historians have evidence of its use initially in China, Egypt, India and Mesopotamia.

There are several types of abacuses, but as our goal is mathematics, there is no need to talk about all the existing types. We will highlight the school abacus used in Brazil, which is used to facilitate the understanding of the base 10 numerical system and basic operations. This abacus is made in a rectangular shape, usually in wood, with internal rods with 10 balls each, because it is based on the decimal system, which uses 10 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8 and 9). The first rod represents the unit, the second represents the ten, the third represents the hundred, etc. Thus, the more rods, the greater the abacus calculation capacity.

As an example, the largest number that can be represented by an abacus with 4 rods is 9,999, while an abacus with 7 rods can represent numbers up to 9,999,999.