Mato Grosso do Sul, Urukun High School not far from Coiaba.
A day in mid-March!
Dang! Dang! Dang!……
As the school bell rang, a young woman in white pushed open the door of Class 1, Grade 1, and came in on time!
"Stand up!"
"Hello, teacher!"
"Hello, classmates!"
After glancing around and seeing all 41 students, she said: "Please sit down!"
Swish! Swish! When Teacher Jessica finished speaking, the whole class sat up in response.
Teacher Jessica was a nun before, and she is now. She is not a local, but was sent here by the Brazilian Anglican Church at the call of the king.
Jessica, a nun teacher, has been teaching in this rural school in Coiaba for three months. She is very beautiful and gentle. Just like her name Jessica represents wealth and means a popular girl, she also
Very popular. In this remote village, Jessica's beauty attracts more attention. She is a rare beauty in the Ulukun area. Her slightly playful face always has a smile on it!
Jessica is kind-hearted and even if a small bug falls on her body, she will gently remove it and put it in a safe place. She often teaches students to be kind and not to bully people or small animals!
There was a barn swallow's nest in the classroom. She knew about it and allowed it to exist. In order to frighten the naughty students, she warned her several times in an easy-going tone.
"If someone dismantles it..."
Jessica pointed to the bird's nest on the beam, pouted, put her hands on her hips and threatened, "I'll make you run 10 laps of the playground as a penalty for three days!"
"Okay, let's start math class~"
Bang~ slammed the table and started flipping through the books!
Chirp… Chirp…
The little swallow flew into the classroom, as if entering an uninhabited land, flying and circling happily, flying back to the nest for a while, and jumping around on the desk for a while, not taking dozens of classmates seriously at all!<
/p>
And the students turned a deaf ear to the 'invading' birds, as if they were like air!
"In the first two lessons, we learned about the relationship between life and mathematics. From today on, we will truly enter the world of junior high school mathematics. We will take a new step in primary school mathematics: from zero to negative numbers."
Having said this, Jessica drew a large circle in the middle of the blackboard, wrote the word "negative" to the left of the large zero, and drew an arrow, pointing from zero to negative.
"Everyone opens the textbook and looks at the examples, and then does the exercises in the book. Anyone who has questions raises their hand to ask."
……
The students are all reading the textbooks carefully and doing exercises.
Suddenly, a student named Angelou raised his hand. Teacher Jessica nodded to him, and he stood up and asked: "Teacher, why do we use a minus sign to represent negative numbers?"
"Because mathematics pursues simplicity, writing negative every time is too troublesome and not conducive to calculation. Therefore, mathematics has introduced many symbols.
For example, pi is "兀", such as "h" which represents height. The same goes for "one" here, it is not a minus sign, you have to read "one" as negative."
As Teacher Jessica spoke, she wrote "ten" and "one" on the blackboard, and pointed at "one".
"In the addition and subtraction of rational numbers that you will learn in the future, you will often encounter this problem, which "one" is the minus sign and which "one" is the negative sign.
Only by accurately judging the minus sign and the negative sign can we perform rational number operations. The negative sign represents the attribute of the number after the negative sign, which is a negative number. The minus sign is the operation rule.
Although the two have similarities, they must not be confused. Only numbers with the same attributes can be added and multiplied at the same time.
Remember, rational numbers can only be added and multiplied. I will learn why later."
After a while, another classmate raised his hand and asked: "Teacher, why are we discussing errors here when we don't know the quantity of the standard mass?"
"This question gets to the point. Let's discuss a question first: Suppose there is a vast mountaintop plain on the Brazilian plateau. There is a 200-meter-high hill in this plain, and the mountain where the plain is located is 1,500 meters above sea level.
Now let me ask you, how many meters is the altitude of this hill? This classmate, do you know the answer to this elementary school math problem?"
"The hill is 1,700 meters above sea level."
"Correct answer. Why is it 1700 meters instead of 200 meters?"
"Because the question asks about altitude."
"Very good. It's just the word "elevation". This is the "standard" in your question just now.
If you build ten 100-meter buildings and build them in ten places in the world, you may get ten different altitude values.
Just like Cuiabá, the country is now building various facilities such as signal towers and high-rise buildings here, but the buildings built on the plains are different from those built on the Brazilian plateau.
The buildings are all 100 meters, so why are there ten altitude values? Because the altitude is the standard chosen. The altitude values in the ten places are different, resulting in different altitude values of the buildings."
"Take another example of a 100-meter building. You built ten buildings. After the architect's final accurate measurement, some were 30 centimeters higher and some were 20 centimeters lower. These two values are errors."
Jessica wrote "30" on the blackboard.
"Where do these two quantities come from? They are derived from the 100-meter building you want to build. This 100 is the ideal number, or target.
In real life, due to various reasons, the ideal state is not achieved and errors occur.
To sum up, here is a question: When discussing problems in real life, there must be a prerequisite, or standard. In mathematics, this standard is called the origin, represented by "O"."
As Jessica spoke, she drew a straight line on the blackboard, highlighted a point with red chalk, and wrote "O" under the red point.
"The points to the left of this origin represent negative numbers, and the points to the right represent positive numbers. Do you understand this?"
"Understand."
"Okay, I have a question for you: In the question about the building just now, how many meters is the height of this building?"
"100 meters."
"Why did 100 meters become zero?"
The classmates were thinking. While the classmates were thinking, no one raised their hands to answer. After a while, a child with an oriental face raised his hands.
Teacher Jessica raised her hand to signal to stand up and answer.
"It should be for the convenience of expression that the value of 100 is not considered. It is only set as the origin and represented by zero, and then only the error issue is discussed."
"Very good, the answer is accurate." Teacher Jessica pressed her hand down and motioned the two standing people to sit down.
"The zero we have now is no longer the zero in elementary school. It is no longer there. It is a relative position. We call it the origin.
Keeping this in mind, we will continue to change the position of this origin in the future to find the positive or negative number relative to the original origin that corresponds to the positive or negative number of the new origin.
For example..."
Tang Ning is in charge of primary education in Brazil, especially in the five subjects of physics, mathematics, Chinese language and politics, and history. Tang Ning personally supervised, compiled and final reviewed.
As an outstanding talent produced by the nine-year compulsory teaching system, Tang Ning knows how to do it.
Although Tang Ning has almost forgotten the nine years of teaching after attending college and studying abroad, she still knows the basic framework.
Mathematics and physics, Tangning is not very proficient in advanced studies, but the basics are more than enough. It is not difficult to write, and the framework and participation in operations are directly provided to fill in the details.
Mathematics and physics are easy to solve. Chemistry and biology are two subjects that are exposed at the end of the nine-year compulsory system. Tangning is even more familiar with it. As a biology graduate, these basics are not easy to solve. Plus nine years
It was very easy to write about my compulsory education experience.
Brazil’s nine-year compulsory system does not include music or art classes. The main subjects are Chinese, mathematics, physics, politics, history, physical education, and biology and chemistry, which are added successively in the second and third grades of junior high school.
In terms of physical education and science, Tangning is very easy to solve. He spends the most time on Chinese, history, and politics.
Tang Ning almost scratched her head when writing textbooks for these three subjects.
Chinese, politics, and history are three subjects closely related to the country and must have corresponding national attributes.
This is not easy to operate. You have to collect a lot of things, refer to them, and then add some personal stuff to write it. The process is very painful.
The Chinese language is not bad. I chose some excellent articles and added more patriotic content. In some articles, Tang Ning directly wrote the composition herself.
Politics and history, Downing was extremely painful when writing the history of Portugal and Brazil.
The history starts from the Lusitanians and Celts, to Rome, then to the first Suebi Kingdom of Galicia, then to the history of Galicia and Portugal during the recovery of the lost territories, and finally to the Portuguese Empire.
The Age of Sail and Brazilian History.
Political subjects, its textbooks are even more difficult to write.
In order to establish the meaning of the country and explain and identify the state capitalism, fortunately, Tang Ning's professional counterpart, who has a master's degree and a doctorate in anthropology and sociology, compiled them after a lot of hard work.
Fortunately, this is still primary education. It involves high school and university, politics and history, and the pain is even more excruciating.
But after some time, I finally got it out.
This chapter has been completed!