It has long been a mystery of Aztec arithmetic: What is three arms plus five bones? Now researchers know: five hearts. The odd symbols had been noted for centuries -- thousands of them appear in Aztec ...

It has long been a mystery of Aztec arithmetic: What is three arms plus five bones? Now researchers know: Five hearts. The odd symbols had been noted for centuries; thousands of them appear in Aztec ...

Long known for their cool circular calendars and practice of human sacrifice, Aztecs were also math whizzes. Aztecs used hand, heart and arrow symbols to represent fractional distances when ...