A little knowledge about flat year and leap year

1. Courseware knowledge of leap year and peace year.

2. Little knowledge of leap years in normal years

Courseware knowledge of leap year and peace year 1. How to write the teaching plan for the open class in the third grade of elementary school in the flat year and leap year?

Teaching objective: 1. Make students understand the knowledge of normal year and leap year and judge whether a year is a normal year or a leap year.

2. Help students to establish a longer concept of time and cultivate the ability to observe and summarize carefully. 3. Through teaching, cultivate students' good habit of cherishing time and carry out patriotic education for the camera.

Teaching emphasis: Knowing the knowledge of normal year and leap year can help us to judge whether a year is a normal year or a leap year. Teaching difficulty: discover and master the judgment method of leap year.

Teaching preparation: multimedia courseware, small research before class. Teaching process: First, review and introduce students. What did we learn last class? Let's recall the songs together.

Have you all remembered the moon and the moon? The teacher is coming to test you! Please listen carefully to the requirements. Teachers can apply for a month at will. If the male students in big month stand up, if the female students in small month stand up. Second, observe the calendar and explore the new teacher's last report in February. Q: Why didn't you move when the teacher reported in February just now? (Because February is a special month) Yes! February is a special month, with 28 days in some years and 29 days in some years.

Let's call February a year with 28 days (blackboard writing: flat year) and February a year with 29 days (blackboard writing: leap year). That's what we're going to learn today-knowing the flat year and leap year.

Yesterday, the teacher assigned you a monthly calendar on page P49 of your study book. Please take out a small study and communicate in groups of four. (Health Report) A. Some years have 28 days in February, and some years have 29 days in February; B every three years, one year is a leap year; C there are 1 leap years every four years.

Teacher: It's really a very careful observation. There are usually three normal years and 1 leap year every four years.

So we observed1993-which year was 2004 a leap year? Yes, 1996, 2000 and 2004 are leap years. What's the difference between the two? According to this rule, what year is the next leap year? Is this a flat year or a leap year? You may ask: Why is there a difference between a flat year and a leap year? Let's go to the knowledge gas station to refuel! Please look at the big screen. Teacher: I see, there are 1 leap year every four years.

What is the relationship between the years of these leap years and 4? Let's divide these years by four and see what we can find. The teacher shows the calculation results: (courseware)1993 ÷ 4 = 498 ...12001÷ 4 = 500 ...11994 ÷ 4 = 997 ÷ 4 = 499 ...11998 ÷ 4 = 499 ... 21999 ÷ 4 = 499 ... 323 Teacher: Yes, that is to say, years that are multiples of 4 in the Gregorian calendar are generally leap.

(Blackboard) To judge whether a year is a leap year, you can divide one year by four to see if it is divisible. The only divisible year is leap year. Next, please judge whether the following year is a flat year or a leap year according to the calculation results. And explain why.

Courseware shows the calculation results: (courseware)1876 ÷ 4 = 4691936 ÷ 4 = 4841894 ÷ 4 = 473 ... 21996 ÷. Please look at the big screen. There is a leap year every four years, and the time difference is not exactly 24 hours, but 23 hours 15 minutes and 4 seconds, so a leap year of four years is 44 minutes and 56 seconds longer. It seems that the error is small, and the error will be big after a long time.

There will be three more days every 400 years, 2: 53: 20, so there should be three fewer days every 400 years. In order to facilitate the calculation, the rule of "leap every four years, not leap in a hundred years, and leap again in four hundred years" has been formulated.

So scientists make a supplementary provision: a year is a whole hundred years, and it must be a multiple of 400 to be considered as a leap year. Teacher: Oh, it is a leap every four years, not every hundred years, but every four hundred years.

Please open page 49 of the book and read the next paragraph. (Students read together) Do you understand? Who can tell me how you judge whether a year is a flat year or a leap year? What's your method? What about a hundred years? Third, consolidate the exercise, expand and extend 1, take out the exercise book, and calculate with the method just learned to see which year is a leap year. 19971999 2000 2004 20102. Can you quickly judge whether the next year is a flat year or a leap year with the teacher's method just now? Just try it.

1996 201221051998 2003 2004 IV. Summarize, evaluate and improve the whole class. What did you gain from this class? If you want to learn more about the year, month and day, you can also look up these materials online.

2. Knowledge of flat years and leap years

A normal year refers to a year in which there is no leap day in the solar calendar and no leap month in the lunar calendar. The establishment of leap year is to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations. The number of years in A.D. can be divisible by 4 as a leap year, but the number of whole hundred years (both digits are 0) must be divisible by 400 as a leap year (for example, 1900 is not a leap year), and everything else is a flat year.

The solar calendar has 365 days in a normal year, 366 days in a leap year and 29 days in February. February 28th of Gregorian calendar. Leap year * * * has 366 days (February is 1- 1 day, 29 days, 3 1 day, 30 days, 3 1 day, 3 1 day respectively).

Extended data

The judgment method of leap year:

1. 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. A year with a large number is a leap year if it can be divisible by 3200 and 172800. For example, 172800 is a leap year, but 86400 is not (because 3200 is divisible, but 172800 is not) (this is calculated according to 365 days in a tropical year, 5h48'45.5').

3. How to judge a flat leap year

Understanding the instructional design of Peace and Leap Year: Understanding the instructional design of Peace Leap Year 1 Through independent research, we can distinguish between a normal year and a leap year, know the February day of the normal year or leap year, and remember the days of the normal year and leap year. 2. In the process of comparison and induction, we can experience daily life and mathematical knowledge at close range and cultivate the significance of mathematical application. Remember the number of days in a normal year and a leap year; Master the judgment method of normal year and leap year. 2. In the process of solving problems, experience the daily life closely related to mathematical knowledge and cultivate the temporality and ability of mathematical application. 3. Understand the laws of motion of some cosmic objects.

Su Jiaoban: Understanding the teaching design of year, month and day-normal year and leap year Su Jiaoban: Understanding the teaching objectives of year, month and day-normal year and leap year, 1, understanding the time unit year, month and day, and understanding the relevant knowledge of big and small months, normal year and leap year; 2. Remember the months and days of the normal year and leap year, so as to preliminarily judge whether a year is a normal year or a leap year, and help students establish a longer concept of time.

Small knowledge of leap year in normal year 1. Knowledge of flat years and leap years

A normal year refers to a year in which there is no leap day in the solar calendar and no leap month in the lunar calendar. The establishment of leap year is to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations. The number of years in A.D. can be divisible by 4 as a leap year, but the number of whole hundred years (both digits are 0) must be divisible by 400 as a leap year (for example, 1900 is not a leap year), and everything else is a flat year.

The solar calendar has 365 days in a normal year, 366 days in a leap year and 29 days in February. February 28th of Gregorian calendar. Leap year * * * has 366 days (February is 1- 1 day, 29 days, 3 1 day, 30 days, 3 1 day, 3 1 day respectively).

Extended data

The judgment method of leap year:

1. 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. A year with a large number is a leap year if it can be divisible by 3200 and 172800. For example, 172800 is a leap year, but 86400 is not (because 3200 is divisible, but 172800 is not) (this is calculated according to 365 days in a tropical year, 5h48'45.5').

2. leap year information in normal years

leap year

Meaning: The leap year is established to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations. The year with time difference, that is, the year of leap day, is a leap year.

The rules for judging leap years in the Gregorian calendar are: leap every four years, not leap in a hundred years, and leap again in four hundred years.

Simple calculation method of leap year in Gregorian calendar (a year that meets one of the following conditions is a leap year)

1。 Divisible by 4, but not by 100.

2。 Divisible by 100 or 400.

Details are as follows:

Leap year refers to the year with leap day in Gregorian calendar or summer calendar, and the year with leap month in China lunar calendar.

The period of the earth's orbit around the sun is 365 days, 5 hours, 48 minutes and 46 seconds (365.438+09 days), which is the tropic of cancer. The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year, and accumulates about one day every four years. Add this day to the end of February (February 29th), so that the calendar year of that year is 366 days, and this year is a leap year. 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. Therefore, it is stipulated that the Gregorian calendar year is a whole hundred years, and it must be a multiple of 400 to be a leap year, and a multiple of 400 is not a normal year. For example, 1700, 1800 and 1900 are normal years, and 2000 is a leap year. The calculation of leap year comes down to what is commonly said: a leap every four years, not a leap every hundred years, and a leap every four hundred years.

The average summer calendar is only 354 days a year, which is 0.367 1 day shorter than the 12 months of the lunar calendar. In order to make the first day of each month coincide with the new moon, it is stipulated that the end of 1 1 year will increase by 1 day every 30 years. This calendar year has 355 days, which is a leap year. As a kind of China lunar calendar, the number of days in each month depends on the monthly deficit, and the time of one year is based on 12 months, and the normal year is about 1 1 day less than a tropical year. In order to close the earth's orbit around the sun, that is, the tropic year, one month is added every two to four years, and the added month is a leap month. The year with leap month is 13 months, and the calendar year is 384 or 385 days. This year is also called leap year.

Average year (as opposed to leap year)

There is no leap day in the solar calendar and no leap month in the lunar calendar. There are 365 days in the solar calendar and 354 or 355 days in the lunar calendar.

Or a year when the crops are very common.

The number of years in AD can be divisible by 4 into leap years, but the number of years in Zhengbai must be divisible by 400. Everything else is a normal year. February in leap year has 29 days. For example, 1996 is a leap year, 2000 is a leap year, and February in a normal year has 28 days, 1900 is a normal year, and 1997 is a normal year.

A year with a leap month in the lunar calendar is called a leap year.

3. Three methods to judge a flat year and a leap year

There are three ways to judge a normal year and a leap year: ① A leap year is a year in which a normal year is divisible by 4 and cannot be divisible by 100.

Otherwise it will be a normal year. (For example, 2004 is a leap year, 1900 is not. ) 2. Leap year is a century year divisible by 400.

Otherwise it will be a normal year. (For example, 2000 is a leap year, and 1900 is not.) ③ For a year with large values, if 3200 and 172800 can be divisible, it is a leap year.

Otherwise it will be a normal year. For example, 172800 is a leap year, but 86400 is not (because 3200 is divisible, but 172800 is not).

Extended data:

/kloc-leap year from 0/950 to 2050: 1952, 1956, 1960, 1964, 1968, 1972. 1996、2000、2004、2008、20 12、20 16、2020、2024、2028、2032、2036、2040、2044、2048。 Leap year * * * has 366 days (February is 1- 1 day, 29 days, 3 1 day, 30 days, 3 1 day, 3 1 day respectively).