How do you judge a leap year? How is a leap year determined?

The Gregorian calendar, which is commonly used in the world, is the Gregorian calendar, which was formerly known as the Julian calendar. According to the Julian calendar, there is one leap year every four years, with 366 days in leap years and 365 days each in the remaining three years (called common years). The number of years in the Common Era that can be divided by 4 is a leap year.

The average length of the Julian calendar in one year is 11 minutes and 14 seconds longer than the actual revolution period, that is, about 3 days per 400 years. Pope Gregory XIII announced in 1582 a change in the calendar, changing the rules for intercalation. A year divided by 4 is a leap year, but a year divided by 100 and 400 is not a leap year.

This would reduce the number of leap years by 3 out of 400 years. Under the Gregorian calendar, there are 97 leap years (366 days per year) and 303 common years (365 days per year) in 400 years, so the average length of each year is very close to the days of the orbital cycle.

1. The meaning of leap years.

A leap year was established to compensate for the difference between the number of days of the year and the actual orbital cycle of the earth caused by the man-made calendar. The year in which the time difference is made up is a leap year.

2. The method of determining leap years.

The law followed in determining a leap year in the Gregorian calendar is: one leap in four years, no leap in one hundred years, and another leap in four hundred years.

A simple calculation of a leap year in the Gregorian calendar: (A leap year is a leap year if one of the following conditions is met)1. Divisible by 4 but not by 100. (For example, 2004 is a leap year, 1900 is not).

2。Divisible by 400. (e.g. 2000 is a leap year).

A leap year is divisible by four, but a common year is not! Remember!! Hehe. Hee-hee.

Do you know how to judge leap years?

Divide the year by 4 to get a whole number for a leap year, otherwise a common year.

Ordinary leap year: A year that is divisible by 4 but not by 100 is an ordinary leap year. (For example, 2004 is a leap year, and 1999 is not a leap year).

Century leap year: A century leap year that is divisible by 400. (For example, 2000 is a leap year of the century, and 1900 is not a leap year of the century).

Leap years are created to compensate for the time difference between the number of days of the year and the actual orbital cycle of the earth caused by the man-made calendar. The year in which the time difference is made up is a leap year. There are 366 days in a leap year (31, 29, 31, 30, 31, 31, 30, 30, 31, 31, 30, 31, 30, 30, 30 and 31 from January to December).

1. An ordinary year is divisible by 4 and not divisible by 100 for leap years. (e.g. 1900 400 = , 2000 400 = 5, then 1900 is a common year and 2000 is a leap year.) )

2. Century years are intercalary years that are divisible by 400. (e.g. 2000 is a leap year, 1900 is not a leap year).

3. For a year with a large value, if it is divisible by 3200 and divisible by 172800, it is a leap year. For example, 172800 is a leap year, and 86400 is not a leap year (because although it is divisible by 3200, it is not divisible by 172800) (this is a return year of 365 days 5h48'''calculated).

Steps to determine a leap year: If the year is a multiple of 100, then divide the year by 400 to get an integer as a leap year, and vice versa as a common year; If the year is not a multiple of 100, then divide the year by 4 to get an integer number, then the digging wisdom is a leap year, and vice versa. The "leap year" in the Gregorian calendar refers to the year in which there is a leap day in the Gregorian calendar, which is called a leap year, and the opposite is a common year, with a common year of 365 days and a leap year of 366 days.

In the Gregorian (Gregorian) calendar, February is 28 days in a common year and 29 days in a leap year. Leap day is celebrated on February 29 of a common month in leap years. Methods of calculating leap years In the Gregorian calendar chronology, most of the years that can be divisible by 4 are leap years, the years that can be divided by 100 whole limbs and not divisible by 400 are not leap years, and those that can be divisible by 3200 are not leap years, such as 1900 is a common year, 2000 is a leap year, and 3200 is not a leap year.

The "leap year" of the lunar calendar is a leap year in the old Chinese calendar, and the year with a leap month is called a leap year. A typical year is 12 months, 354 or 355 days, while a leap year is 13 months, 383 or 384 days.

Summary. 1.Ordinary leap year:

A Gregorian calendar year is a multiple of 4 and not a multiple of 100, and is an ordinary leap year. (e.g. a year is a leap year); 2. Century leap year: The Gregorian calendar year is an integer hundred, and it must be a multiple of 400 to be a century leap year (for example, 1900 is not a leap year of the century, and 2000 is a leap year of the century).

1.Ordinary Elimination Concealment Leap Year: If the Gregorian calendar year is a multiple of 4, take the state and not a multiple of 100, it is an ordinary leap year.

(e.g. a year is a leap year); 2. Century leap year: The Gregorian calendar year is an integer hundred, and it must be a multiple of 400 to be a century leap year (for example, 1900 is not a leap year of the century, and 2000 is a leap year of the century).

Leap years are established to make up for the time difference between the number of days of the year and the actual orbital cycle of the earth caused by the man-made calendar. There are 29 days in February in leap years, and there are 366 days in the year[1]. An ordinary leap year means that the Gregorian year is a multiple of 4, and Shiliang is not a multiple of 100, and a leap year of the century must be a multiple of 400.

Pre-1582 convention: every leap every four years; If a (positive) in A.D. is divisible by 4, then it is a leap year; If the b (positive number) of the year B BC is divided by 4 and the remainder of 1, then it is also a leap year.

1. Leap years are divided into "Gregorian calendar" and "lunar calendar" The concept of leap year in the Gregorian calendar and the lunar calendar is different. The leap year that we often discuss is actually a leap year in the Gregorian calendar. A year in the Gregorian calendar with a leap day is called a leap year.

A year in which there is a leap month in the lunar calendar is called a leap year. For example, 1995 and 2001 were leap years, but not leap years. In 2000, the Gregorian calendar was a leap year, and the lunar calendar was not a leap year. Here's a comparison from 1982 to 2042.

2. Determination of leap years in the Gregorian calendar The general common sense is that there is a leap year in 4 years, and a year divisible by 4 is a leap year, but this is not necessarily the case. Which years are leap years? How can you tell if a leap year?

In the Gregorian calendar year, a year with a leap day is called a leap year, which is 365 days in a normal year and 366 days in a leap year. Since the Earth's circumnavigation cycle around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds, which is a return year, the Gregorian calendar defines a year as 365 days. The remaining time is about four years and accumulates one day, which is added to February and fixed in February, so that in a normal year there are 365 days per year, 28 days in February, 366 days in leap years, and 29 days in February.

There are 97 leap years in every 400 years. The usual calculation of leap years: the number of years in the Common Era is divisible by 4, that is, leap years; However, a year divisible by 4 is not necessarily a leap year, such as 1700 and 1900.

The year at the turn of the century, divisible by 100 but not divisible by 400 is a common year; A leap year is divisible by 100 and also divisible by 400. For example, 2000 A.D. is a leap year, while 1000 A.D. and 3000 A.D. are not. Here's a formula for calculating leap years, if you're interested, you can take a look.

3. Estimation of Leap Months in the Lunar Calendar A year in which the lunar calendar has a leap month is called a leap year, but it is now customary to also call it a leap year (so it is easy to be confused with a leap year in the Gregorian calendar). A normal year is 12 months, 354 or 355 days, and a leap year is 13 months, 383 or 384 days. The lunar calendar does not have the title of the thirteenth month, and the leap month is repeated in the same month from February to October according to the rules of the calendar, and the repeated month is called the leap month, such as the leap month after April is called leap April.

The law of leap years in the lunar calendar is one leap in 3 years, two leaps in 5 years, and seven leaps in 19 years, and the specific month of the leap month is inferred according to the rules of the lunar calendar, mainly according to the 24 solar terms of the lunar calendar to determine, and usually the month with only one solar term (generally a small month) is set as a leap month to make up. The number of leap months in the lunar calendar is the same as the number of days in a normal month, which is 29 or 30 days. The lunar calendar is basically a cycle of 19 years, corresponding to the same time in the Gregorian calendar.

For example, May 27, 2001, May 27, 1982 and May 27, 1963 in the Gregorian calendar are all the fifth days of the fourth month of the leap month.

The formula for leap years in the third grade of primary school: divide the year number by four, and the rest is a leap year. The number of days is 366, and the number of days is 29 days in February.

The year name is divided by four, and there is more than one, two, three. Ordinary year 365, February 28 days. In 2000, it was difficult to calculate the exception.

The divisor is four hundred, and the remainder is a leap year.

A common year is a year in which there are no leap days in the solar calendar or no leap months in the lunar calendar; A leap year is a year in which there are leap days in the solar calendar. Determine whether a year is a common year or a leap year: if the Gregorian calendar year is a whole hundred or a whole thousand, divide the year by 400, if it is divisible, it is a leap year, and if it is not divisible, it is a common year; For other years in the Gregorian calendar, divide the year by 4, if it is divisible, it is a leap year, and if it is not divisible, it is a common year.

The reason for leap years: the Earth's orbit around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds, that is, a return year. The common year of the Gregorian calendar is only 365 days, which is about one day shorter than the return year, and the remaining time is about one day accumulated every four years, so the fourth year adds one day at the end of February, so that the length of the calendar year of the year is 366 days, and this year is a leap year.

There are 97 leap years in every 400 years in the current Gregorian calendar.

According to a leap year every four years, the average number of days per year is to be counted out, so that after 400 years, about 3 days will be calculated. Thus three leap years are reduced every 400 years. So the Gregorian calendar prescribes:

When the year is an integer hundred, it must be a multiple of 400 to be a leap year; A century year that is not a multiple of 400, and even a multiple of 4 is not a leap year.