Aztecs devised sophisticated arithmetic system

By Will Dunham

WASHINGTON (Reuters) - Using written symbols such as hearts, arrows and hands, the ancient Aztecs maintained an arithmetic system that was far more complex than previously understood, scientists said on Thursday.

The Aztecs, an empire in central Mexico toppled by Spanish invaders in 1519, has long been recognized for its sophistication in architecture, engineering, astronomy and other fields. And the new research confirms arithmetic can be added to the list.

The researchers examined hundreds of drawings in two manuscripts dating back to between 1540 and 1544 that were used to document agricultural properties by the Aztec people in the city-state of Tepetlaoztoc, near modern Mexico City.

The Aztecs used a system that included symbols of hearts, hands, arrows, bones, arms as alternatives to using fractions. An examination of these hieroglyphic records showed that the Aztecs used their own calculation system to figure out, for example, the area of a parcel of land.

"What we thought we knew about the Aztec measuring system was a little simplistic. We've determined that it was more complex," researcher Barbara Williams of the University of Wisconsin-Rock County said in a telephone interview.

'NUMERATE SOCIETY'

Williams teamed with Maria del Carmen Jorge y Jorge of the Universidad Nacional Autonoma de Mexico in the study published in the journal Science.

"They used the four mathematical operations of addition, subtraction, multiplication and division. But in almost all of the early societies, they could do everything they needed to do, with just those four. They didn't need square roots. They didn't need trigonometry," Williams said.