135780 wax, 31 days is never bad, 469 winter 30 days, the usual February 28 wax refers to December, the first half refers to: January, March, May, July, August, October, December The number of months and days is 31 days, winter refers to November, April, June, September, November is 30 days. Ordinary years 365 days, leap years, ordinary years can be divided by 4, can not be divided by 100; as the saying goes: four years a leap, a hundred years without leap, four hundred years and then leap 366 days in February, that is, the usual February is 28 days, leap February is 29 days calendar.
The exact calculation method of leap years (according to a regression year of 365 days, 5 hours, 48 minutes and 45.5 seconds) (1), ordinary years that can be divisible by 4 and cannot be divided by 100 are leap years (such as 2004 is a leap year, 1901 is not a leap year) (2), the century year can be divided by 400 is a leap year. (For example, 2000 is a leap year, 1900 is not a leap year.) Divide the year by 4, and the one with no remainder is the leap year, and the remainder is the common year.
![Tell you what you didn't know about leap years[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)