12
365 days
10
890
890
6
200
366
That's approxamately the amount of days it takes the Earth to make one revolution around the Sun
6,939.785 days (rounded) ( 19.000096 years ) (rounded)
Well, different calendars have different prefaces / setups. but their are 365 days or sometimes 366. (only on leap years) in a year.
The inca had 100 calendars.
30 revolutions of Earth around the sun = 10,957.5 days (rounded) 30 consecutive calendars have either 10,956, 10,957 or 10,958 days printed on them.