By combining the Haab and the Tzolkin, the Maya formed the "Calendar Round." This third calendar
functioned like two interlocking cog wheels with specific numbers and day names coinciding once every 52 years.
What made the Maya number system unique?
The Maya developed a complex, base-20 number system that made it possible to record all numbers
using three symbols, a dot representing the number one, a bar representing the number five, and a
shell representing zero . The Maya used this system to record their history and observations. Many
examples of Maya numbers, a series of recurring horizontal bars and dots, appear in the Dresden
Codex—a Maya book from the eleventh century that turned up in Dresden in 1739.
Place value is important in the Maya number system, as it is in our decimal, or base-10, system. Unlike the
decimal system, however, in which we move one position to the left on reaching ten, the Maya moved one
position up, in multiples of twenty. With this system, the Maya counted into the millions.
Credits: Aztec Calendar Stone © Kimball Morrison/South American Pictures;
Codex Madrid Fragment of the Codex of Madrid. Mayan manuscript. Museo de America, Madrid, Spain. Photo © Scala/Art Resource, New York.
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