Final answer:
The two main calendars developed and used by the Mayans were the solar calendar and the sacred calendar. These calendars were important achievements in mathematics and astronomy as they allowed the Mayans to record and predict celestial events and track the passage of time.
Step-by-step explanation:
The two main calendars developed and used by the Mayans were the solar calendar and the sacred calendar. The solar calendar, also known as the Haab, was based on the solar year and consisted of 18 months of 20 days each, with an additional 5-day month at the end. The sacred calendar, also known as the Tzolk'in, was a 260-day calendar that had a cycle of 20 day names combined with a cycle of 13 day numbers.
These calendars were important achievements in mathematics and astronomy because they allowed the Mayans to record and predict celestial events and track the passage of time. The Mayans were skilled mathematicians and astronomers, and their calendars were based on complex mathematical calculations and astronomical observations. The calendars played a central role in Mayan rituals, religious ceremonies, and the organization of their society.