In what ways were calendars useful to Maya, Aztec, and Inca peoples?

I'm trying to study so if you could tell me that'd be great :)

3 answers

i only know that the maya used the calendars for planning religious festivals
https://www.sutori.com/story/the-making-of-different-calendars-the-maya-inca-aztecs
Thanks Ms. Sue, but i need your help no longer. :)