How leap years are calculated

Leap year The leap year of the Gregorian calendar is stipulated as follows: the earth revolves around the sun once called a return year, and the return year is 365 days, 5 hours, 48 minutes and 46 seconds. Therefore, the Gregorian calendar stipulates that there are common years and leap years, and there are 365 days in a common year, which is shorter than the return year, and there are four short days in four years, so one day is added every four years, and there are 366 days in this year, which is a leap year.

However, an additional day in four years is more than four return years, and there will be many days after 400 years, so there are three fewer leap years in 400 years, that is, only 97 leap years in 400 years, so that the average length of the Gregorian calendar year is similar to that of the return year. Therefore, it is stipulated that if the year is an integer hundred, it must be a multiple of 400 to be a leap year, for example, 1900 and 2100 are not leap years.

The earth we live on always revolves around the sun. It takes 365 days, 5 hours, 48 minutes and 46 seconds for the earth to complete one revolution around the sun, which is the day. For convenience, the year is set at 365 days, which is called a common year; In this way, every four years there is about an extra day, and if you add that day to February, there are 366 days in the year, which is called a leap year.

Usually, there are three common years and one leap year every four years. Gregorian calendar years are multiples of 4 and are generally leap years.

According to a leap year every four years, an average of more days are counted per year, so that after 400 years there will be about 3 more days, so that every 400 years there is a decrease of three leap years. Therefore, it is stipulated that the Gregorian calendar year is an integer hundred, and a leap year that must be a multiple of 400 is a leap year, and a multiple of 400 is a common year.

In other words, the earth we live on always revolves around the sun. It takes 365 days, 5 hours, 48 minutes and 46 seconds for the earth to complete one revolution around the sun, which is the day. For convenience, the year is set at 365 days, which is called a common year; In this way, every four years there is about an extra day, and if you add that day to February, there are 366 days in the year, which is called a leap year.

Usually, there are three common years and one leap year every four years. Gregorian calendar years are multiples of 4 and are generally leap years.

According to a leap year every four years, an average of more days are counted per year, so that after 400 years there will be about 3 more days, so that every 400 years there is a decrease of three leap years. Therefore, it is stipulated that the Gregorian calendar year is an integer hundred, and a leap year that must be a multiple of 400 is a leap year, and a multiple of 400 is a common year.

That's what we usually call it:

There is a leap in four years, no leap in a hundred years, and another leap in four hundred years.

Who said that divisible by four is a leap year??

The law followed by the determination of leap years in the Gregorian calendar is: one leap in four years, no leap in one hundred years, and then leap in four hundred years.

This information is very detailed.

Teach you how to calculate leap years, will you?

Leap Year Calculation Method:1. Gregorian leap years are intercalary years that are divisible by 4 and not divisible by 100, on average there will be a leap year every four years, and those that are divisible by 400 in the century year are leap years, for example, 2000 is a leap year, and 1900 is not a leap year, for a year with a large value, if it can be divisible by 3200 and 172800, it is a leap year.

2. Formula: one leap in four years, no leap in one hundred years, and then leap in four hundred years.

The current Gregorian calendar uses the year of return as the basis for calculating "years", and a year of return is approximately equal to days. Since only 365 days are counted in the Gregorian calendar in ordinary years, the result is that after four years, the days will be accumulated, which is approximately equal to one day, so a leap day is added every four years to offset this day. But it's still a little less, so there isn't much time for a while, but when it comes to a hundred years, it will be about a few days apart, that is, more.

Therefore, it is necessary to stipulate the details again, and it is not added until 100 years, so that there will be fewer days every 100 years, and when it comes to 400 years, it will be about a day short, so that 100 years will be added to the runri to basically correspond. But there will still be a slight error, but it is quite small. I just roughly calculated, and the actual difference is very small, very small, negligible, but the accumulation of time can be a hundred years out of the "day" in the inconspicuous decimal number.

Let's calculate the difference together.

How to determine leap years.

The rules followed to determine a leap year in the Gregorian calendar are:

There is a leap in four years, no leap in a 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. 1998 is not a leap year (e.g. 2000 is a leap year).

How to determine leap years.

1. An ordinary year is divisible by 4 and not divisible by 100 for leap years. (For example, 2004 is a leap year, and 1900 is not 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 it is divisible by 3200, but not by 172800).

It is stipulated that the Gregorian calendar year is a whole hundred, and it must be a multiple of 400 to be a leap year, and a multiple of 400 is a common year. For example, 1700, 1800 and 1900 are common years, and 2000 is a leap year. Thereafter, the average annual length is days, with a deviation of 1 day in about 4 years.

Origin of leap years:

The usual explanation is that there are many days, hours, and minutes in a year, and the whole number 365 is still superfluous, and after the accumulation reaches 24 hours in a day, the year in which an extra day is added is a leap year. This explanation just tells everyone how to calculate, and it is something that is set artificially.

The most fundamental reason is that the Earth's orbit around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds (conjunction), which 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 every four years, so the fourth year adds one day at the end of February, so that the length of the calendar year of that year is 366 days, and this year is a leap year.

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

Therefore, the Gregorian calendar stipulates that 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.

The above content reference: Encyclopedia - leap year.

Let me explain again that a year that is generally divisible by 4 is a leap year.

And like 1900

A leap year is only counted as a leap year when such a whole hundred years need to be divisible by 400.

So 2000 is a leap year. Whereas.

2100 is not.

Got it? Good luck!

Divide the year by 4, and divide it as an integer is a leap year, for example, 2008 divided by 4 equals 502, which is an integer, and 2008 is a leap year.

2008 is a leap year, the landlord wrote it wrong, the leap year is 29.

1.Calculation method of leap years: In the Gregorian calendar chronology:

Most of those divisible by 4 are leap years; A year that is divisible by 100 but not by 400 is not a leap year; What is divisible by 3200 is not a leap year; For example, 1900 is a common year, 2000 is a leap year, and 3200 is not a leap year.

2.A year in the Gregorian calendar with a leap day is called a leap year, and the opposite is a common year, which is 365 days in a common year and 366 days in a leap year. In the Gregorian (Gregorian) calendar, February is 28 days in a common year and 29 days in February in a leap year.

February 29 is a leap day in a leap year. 3.Leap year of the Chinese lunar calendar:

In the old Chinese lunar calendar, a year with a leap month was called a leap year. A typical year is 12 months, 354 or 355 days, and a leap year is 13 months, 383 or 384 days.

Old State 4The law followed by leap years: one leap in four years, no leap in one hundred years, and another leap in four hundred years.

The number of days in the lunar month of the old Chinese calendar is determined by the monthly waning, and the time of the year is based on 12 months, and the normal year is about 11 days less than the return year. In order to coincide with the Earth's cycle around the Sun, i.e., the return year, one month is added every 2 to 4 years, and the additional month is a leap month. There are 13 months in a year with a leap month and a calendar year length of 384 or 385 days, which is also known as a leap year.

Reason: The actual time for the Earth to revolve around the Sun is 365 days, 5 hours, 48 minutes and 46 seconds. For the sake of convenience, we calculate the normal year as 365 days, which is actually 5 hours, 48 minutes and 46 seconds less, and the difference is 23 hours, 15 minutes and 4 seconds in four years, that is, nearly one day less in four years.

Therefore, every four years a leap year is set to add this day to February of the leap year to make up for the undercounted time, also known as "every four years a leap", according to the above description, every four years when a leap year occurs the time is not a full 24 hours, so every four years a leap year is counted an extra 44 minutes and 56 seconds. In this way, every 100 years is 18 hours, 43 minutes, 20 seconds and almost a day, so by the whole 100 years of the Common Era, this year is not counted as a leap year, and the time to offset the overcount is called "100 years without leap". According to the above calculation of 100 years without leap, every 100 years there are 5 hours, 16 minutes and 40 seconds, so that every 400 years there are 21 hours, 6 minutes and 40 seconds, which is almost another day, so when the year is 400 times the AD, this year is a leap year, which is called - 400 years and leap.

This is the principle of "one leap in four years, no leap in a hundred years, and another leap in four hundred years". In the same way, 400 years and leap years actually cost 2 hours, 53 minutes and 20 seconds, and after 8 400 years (3200 years), another loss of 23 hours, 6 minutes and 40 seconds. Therefore, when the AD year is a multiple of 3200, it is necessary to subtract a leap year, which means that 3200 and 6400 AD are not leap years, so that the actual time error between the leap year and the revolution is very small.

The calculation method of leap year is as follows: 1. A year that is divisible by 4 and not divisible by 100 is a leap year; 2. A century year that can be divisible by 400 is a leap year, such as 2000 is 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.

How leap years are calculatedIf a year is calculated as 365 days, 5 hours, 48 minutes and 46 seconds, the number of days in a year must be an integer, and it is inconvenient to include zero hours. Therefore, if 365 days are taken as a year, the remaining 5 hours 48 minutes and 46 seconds will accumulate to about one day after 4 years. Therefore, a "leap day" every four years is called a "leap year".

If there is no leap day in that year, it is called a common year. So, in a normal year, there are 365 days, and in a leap year, it is 366 days.

Leap year is a noun in the Gregorian calendar year, which is mainly divided into ordinary leap years and century leap years. 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 artificial calendar. There are 366 days in a leap year, and the months from January to December are 31 days, 29 days, 31 days, 30 days, 30 days, 31 days, 31 days, 31 days, 31 days, and 31 days.