Secondary school in the town of Urukun, not far from Coiaba, in the state of Mato Grosso do Sul.
A day in the middle of March!
clang! clang! clang! …
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 students!"
After glancing around and seeing all 41 students, she said: "Please sit down!"
Uh-huh! Uh-huh! After 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 country, 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 a kind-hearted person. Even if a small insect lands 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!
"My Healing Game"
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~ He slammed the table and started flipping through the books!
Chirp… Chirp…
The little swallow flew into the classroom, as if entering a deserted place, flying and circling happily, flying back to the nest for a while, and jumping around on the desk for a while, not taking the dozens of classmates seriously at all!
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. Starting today, 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, raise their hands and ask."
…
The students are all reading the textbooks carefully and doing exercises.
Suddenly, a student named Angelo 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 "兀", such as "h" indicating 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 and negative signs 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 an arithmetic rule.
Although the two have similarities, they must not be confused. Numbers with the same attributes can be added and multiplied at the same time.
Remember, rational numbers only have addition and multiplication. The specific why will be learned 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 mountain in this plain, and the mountain where the plain is located is 1,500 meters above sea level.
Now, what 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 1,700 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 it builds in the plains are different from those built in the Brazilian plateau.
The buildings are all 100 meters, why are there ten altitude values? Because the criterion chosen is altitude. The elevation values of the ten places are different, resulting in different elevation 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 metres."
"Why did 100 meters become zero?"
The classmates are thinking. While the students were thinking, no one raised their hand to answer. After a while, a child with an oriental face raised his hand.
Teacher Jessica raised her hand, signaling 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 for 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 keep changing the position of this origin in the future to find out what positive or negative number represents the positive or negative number relative to the original origin corresponding to 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 reviewed the final review.
As an outstanding talent produced by the nine-year compulsory teaching system, Tang Ning knew how to do it.
Although Tang Ning had almost forgotten the nine years of teaching after attending college and studying abroad, she still knew the basic framework.
Mathematics and physics are not very proficient for advanced students, but the basics are more than enough. It is not difficult to write, and it directly provides the framework and participates in the operation 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. Tang Ning is even more familiar with them. 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.
In Brazil's nine-year compulsory system, there are no music or art classes. The subjects are mainly Chinese, mathematics, physics, politics, history, and biology and chemistry are added successively in the second and third grades.
In terms of science, Tang Ning 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 it, and then add some private stuff to compile it. The process is very painful.
The Chinese language was not bad. I chose some excellent articles and added more patriotic content. For some articles, Tang Ning directly wrote the essays herself.
Politics and history, Downing was extremely painful when writing the history of Portugal and Brazil.
Fortunately, this is still primary education, involving higher education in high school and university, politics and history, and the level of pain is even more excruciating.
But after some time, I finally got it out.
