135780 Latin formula
The first half refers to: 1, March, May, July, August, 10, 12, and the winter index is 1 1, April, June and September.
The 365 days in a normal year, leap year and normal year can be divisible by 4, but not by 100; As the saying goes, every four years is a leap, not a leap for a hundred years, and then a leap for four hundred years. In a balanced year, February, which is usually 28 days, is a leap year with 29 days.
Extended data
Accurate calculation method of calendar leap year (calculated according to the return year of 365 days, 5 hours, 48 minutes and 45.5 seconds), leap year is a year in which ordinary year is divisible by 4 and cannot be divisible by 100 (for example, 2004 is a leap year, 190 1 is not a leap year), and century year is a leap year in which it is divisible by 400.
The average solar year is 365 days, the average lunar year is 354 days or 355 days, and very few days are 353 days. Between the first year of A.D. and 5000 A.D., there were only the following years with 353 days in the lunar calendar: 780, 1620, 1965, 2372, 3620, 3903, 3965, 4 186 and 4248.