Why is a lesson 40 minutes, and a lesson is 40 minutes or 45?

After 40 minutes, you will lose concentration. It doesn't work well.

A lesson is 45 minutes.

In 1998, in order to promote quality education.

Effectively reduce the learning burden of primary and secondary school students, the Ministry of Health and the State Bureau of Technical Supervision.

The "Hygiene Standards for Primary School Students' One-day Learning Time" were jointly issued.

The one-day study time for middle school students refers to the time for class and extracurricular self-study in a day (excluding recess), which should not exceed 8 hours for high school students and 7 hours for junior high school students.

Middle and high school students should not read more than 40 minutes in the morning every day; 4 classes in the morning; 2 classes in the afternoon for junior high school and 2 or 3 classes for high school; Extracurricular self-study should not exceed 2 classes. Each lesson lasts 45 minutes.

In accordance with the provisions of Article 5 of the Regulations on School Health Work of the former State Bureau of Fan Education Commission:

Students arrive at school no earlier than 7:50 a.m. in primary schools and no earlier than 7:30 a.m. in secondary schools. Departure time of primary school no later than 16:00

30, secondary school no later than 17:30". All districts and counties are allowed to make appropriate adjustments in light of the actual conditions of their own regions and the seasonal changes in the eradication of the eradication.

At the same time, it also stipulates that schools should reasonably arrange students' study time. Students' daily study time (including self-study) is no more than 6 hours in primary school, 8 hours in secondary school, and 10 hours in university.

The meaning of 20 lessons and 40 class hours is that there will be so many lessons in a period of time, for example, if there are 20 classes, he will calculate it according to a single session, and then it will be carried out 20 times, so a meaning, and then 40 class hours, it is calculated according to the unit of class hours.

Generally, there will be two class hours in a lesson, so a unit of this kind is calculated, so 20 lessons, 40 class hours, is such a meaning, and it expresses the main meaning of 20 lessons. And 20 lessons is also a way for everyone to express themselves, and everyone generally does not use class time to express, but only uses how many lessons to express.

In this case, it is usually the amount of courses that appear in a semester of college.

If one lesson is 45 minutes, four lessons are 3 hours.

Solution: Because the duration of a class is 45 minutes.

Then the duration of 4 lessons is 45x4=180 minutes.

And because 1 hour = 60 minutes.

then 180 minutes = 180 60 = 3 hours.

That is, the duration of four lessons is 3 hours.

The nature of the four arithmetic

1. Additive properties.

From addition sells the old commutative and associative laws.

It can be obtained, several additions are added, and the position of the addition can be exchanged arbitrarily. Or add a few additions and then add them to the other additions, and their sum does not change.

2. Subtractive nature.

1) Subtracting the sum of two numbers from a mid-rise number is equal to subtracting each addition of the sum from this number in turn.

2) The difference between one number and two numbers is equal to the number of the servant first subtracting the subtracted number in the difference, and then adding the subtraction.

3. Multiplicative properties.

1) Multiply the product of several numbers by a number, so that any factor in the product can be multiplied by this number, and then multiplied by other numbers.

2) Multiplying the difference between two numbers by one number allows the subtracted number and the subtracted number to be multiplied by this number respectively, and then the resulting product is subtracted.

The above content reference: Encyclopedia - Four Operations.

Finally, 45 minutes per lesson is in line with the teaching schedule in our country。In the case of such high-intensity learning in China, 45 minutes per class can make students have an effective learning time of 315 minutes in a day, which can effectively meet the teaching arrangement of China's curriculum and do not delay students' normal holidays and spare time.

If there is anything missing, please feel free to add it.

Every class in school is 45 minutes, because when students are concentrating on learning and listening to the class, 45 minutes is the most appropriate learning time and the most scientific and efficient management.

45 minutes can allow the teacher to finish the key knowledge and at the same time give the students to digest, at this time the cohesion of the two sides can still be supported.

Too long will affect children's attention, science says that the best time for people to concentrate is 45 minutes, if the time is too short, it is also detrimental to the teacher's scheduling. When I was in college, one class lasted an hour and a half, which was relatively long.

For the same 1 lesson, 40 minutes in elementary school and 45 minutes in middle school, what are the considerations for such a setting? This is a question that many people don't usually consider. Some people even think that the time for each class in primary school is relatively short, is it to make it easier for primary school students to go to the toilet?

40 minutes per lesson in elementary school is not something that is innate.

Some people feel that there is no reason why one lesson in primary school is inherently 40 minutes. In fact, this statement is also incorrect. As a post-80s generation, when I was in elementary school in the late 80s, the time for one class in primary school was still 45 minutes.

By the time I was in the upper grades of elementary school, the duration of each lesson had been reduced from 45 minutes to 40 minutes. Of course, in the memory of the post-70s, primary school must be 45 minutes per class, and in the memory of the post-90s and post-00s, one class in primary school will definitely not be more than 45 minutes, and even, in some places, the time for one class in primary school is only 35 minutes.

What is the basis for the 5-minute time difference between 1 class in elementary school and 1 class in middle school?

There is now a time difference of 5 minutes between 1 class in elementary school and 1 class in middle school. 5 minutes, it's not too long, why is this gap widened? It is generally believed that the attention span of primary school students often lasts only 10 to 20 minutes at a time, which is shorter than that of middle school students.

Therefore, the time of one primary school class is set shorter, which is more conducive to the overall arrangement of time. Generally speaking, 20 minutes of teaching and 20 minutes of homework are more suitable for primary school teaching. As a middle school student, it is relatively easier to concentrate a little bit, and the class time is appropriately arranged for a longer time, and the middle school student can also adapt.

There are only 40 minutes in one class of elementary school, is it a factor that takes into account the frequency of toilet visits for elementary school students?

Some people also think that the reason why primary school students only have 40 minutes in one class is because primary school students tend to go to the toilet more often than middle school students. If one class in primary school is too long, it will affect the normal running of primary school students to the toilet, which is not good for the health of primary school students. There is no official statement on this reason.

However, there is actually some truth to this statement. Under normal circumstances, middle school students rarely raise their hands to ask for the toilet in class, and everyone can hold back. And the frequency of primary school students raising their hands to go to the toilet is indeed very high.

It is indeed more reasonable to schedule one class to be shorter.

First, primary school students have poor attention span, and too long class time is not conducive to their learning of knowledge. Second, it is for the sake of the body of elementary school students, who go to the toilet more frequently in elementary school, and too long a class time may affect the student's body. Of course, there is also a saying that a 40-minute session, plus other activities such as recess, is just enough to arrange the day.

Because elementary school students do not have a long attention span, and their comprehension of knowledge is relatively slow. Therefore, the class time is set at 40 minutes, which can make it easier for students to learn.

Because the curriculum of primary school is arranged according to the age of primary school students and the level of receptivity of knowledge, 40-minute lessons are more conducive to the realization of children's ability to accept knowledge.

Because children's attention span is not that long.

During the lesson, the children's minds drift out during the lesson, and 40 minutes can make the children have a sense of restraint and concentration.

To protect the eyes. Elementary school students are at an age of eye development, and if waiting for a long time for a blackboard and textbook can cause excessive eye fatigue, the 40-minute class time will not spread the lesson too much, but also give the students' eyes a moderate relaxation.

A class of 40 minutes, 54 lessons is how many hours.

40 54 60 = 36 hours.