How to calculate leap year?

① A leap year is a year in which ordinary years are divisible by 4 and cannot be divisible by 100. (For example, 2004 is a leap year, 1900 is not. )

② Leap year can be divisible by 400 in century year. (For example, 2000 is a leap year, 1900 is not. )

③ For a year with large numbers, if it can be divisible by 3200 and 172800, it is a leap year. For example, 172800 is a leap year, but 86400 is not (because 3200 is divisible, but 172800 is not).

It is stipulated that the Gregorian calendar year is an integer hundred, and it must be a multiple of 400 to be a leap year, not a multiple of 400 to be a flat year. For example, 1700, 1800 and 1900 are normal years, and 2000 is a leap year. Since then, the average annual length is 365.2425 days, with a deviation of about 4 years 1 day.

According to a leap year every four years, the average annual increase will be 0.0078 days, which will be about 3 days after 400 years. So every 400 years, three leap years will be reduced. The calculation of leap year comes down to what is commonly said: leap every four years; Do not leap in a hundred years, and leap again in 400 years.

Extended data:

Leap year from 1950 to 2050:

1952、 1956、 1960、 1964、 1968、 1972、 1976、 1980、 1984、 1988、 1992、 / kloc-0/996、2000、2004、2008、 20 12、20 16、2020、2024、2028、2032、2036、2040、2044、2048。

The leap year has 366 days (February 1- 1 day, 29 days, 3 1 day, 30 days, 3 1 day, 3 1 day.

A normal year has 365 days (February 1- 1 day, 28 days, 3 1 day, 30 days, 3 1 day, 30 days, 3 1 day, 3 1 day.