I got into trouble in the first math class after junior high school! The math teacher stood on the platform and shouted, "Class!" "The students shouted in unison;" Hello, teacher! "Of course, I am no exception! The teacher said:
"Please open your books and turn to page five!" I shouted, "Oh! Open the book on page 105! " Suddenly, teachers and classmates turned to me and came slowly. At that time, I was scared.
The teacher asked me, "Why do you want to open page 105?" ? Do you know all the previous contents? ""no! Don't! Don't! Sorry, teacher! That's not what I meant. I just think it's funny, just kidding.
Already! "I hurriedly replied.
"So! Why don't you sit down and reflect and give me an explanation after class? " The teacher asked. At this moment, I don't seem to be afraid, because the teacher is so good, I quickly ordered.
Head, replied: "Yes!" I have been reflecting on my mistakes ever since. Unconsciously, time passed and the bell rang. I found a teacher who forgave me and told me to respect others.
Love cannot be a joke!
Today, our class had a math lesson about parallelogram area.
This math class begins with a story: a group of sheep bumped into a rectangular piece of wood on the fence while grazing, and turned it into a parallelogram. The master looked puzzled. He thought, What hasn't changed? What has changed? friendship
A classmate said: "The shape has changed, the height has changed, and the area has also changed, but only the circumference has not changed." I thought to myself: the shape is changed from rectangle to parallelogram; The height of rectangle is higher and the height of parallelogram is lower; flat
The area of quadrilateral is still smaller than that of rectangle. The more crooked the parallelogram, the smaller the area; What about the circumference? It's the same anyway.
The teacher asked, "What is the area of the parallelogram?" A classmate said, "It's cardinal multiplication and height." Teacher Li asked us to try this method. We open Figure 8 on page 18 of the math book, which is a parallel four.
Edge shape. Let's count the squares first, and then multiply the height by the base. We never thought it was right. We all agree with this classmate. Another student said, "Cut it along the height of the parallelogram and put it together again, and it will become longer."
Square. Another student said, "The base of parallelogram is equal to the length of a rectangular row, and the height of parallelogram is higher than the width of rectangle." Teacher Li smiled.
Today's math class let me understand the area of parallelogram, and let me deeply understand the wonders of mathematics. I want to learn math well and make contributions to society in the future.
From the first grade of primary school to now, I have attended countless classes of all kinds, but the most impressive thing is the first math class this semester.
"Jingle bell ..." The bell rang, but it didn't.
After a while, Mr. Jane, the math teacher, came into the classroom with a big smile on her face. "Students, let's meet Yuan in this class. First of all, what kind of circles have you seen in your life? " As soon as the teacher stopped talking, all the students were the same.
Raise your right hand, and everyone's answers are varied: "wheels!" "Clock!" "electric fan!" ..... In short, everyone has seen many circles. Then Teacher Jane said, "Well, since all the students have seen this.
Circle, then let's learn the circumference of the circle now. Do you know what circumference means? ""yes! "The students answered in unison." Perimeter is the length of a circle around an object. Before, everyone studied the rectangle.
The circumference of a shape or a square, then how to calculate the circumference of this circle? Which student would like to talk about his own ideas? "Teacher Jane asked. The students' answers are still various, and some say that the round edges are surrounded by ropes.
Hold on, mark the top, then untie the rope and measure it on the ruler to know the circumference of the circle; Some say roll the cut circle on a ruler once, and then look at the degree to get the circumference. Miss Jane, listen.
Tao: "The students' ideas are very good, but it's too much trouble, so now let's discuss the method of finding the circumference of a circle." "Then the teacher took out four paper circles and four ropes of different sizes and gave them to four students respectively.
Let's measure the circumference of the circle and then measure the diameter of the circle. Everyone carefully measured the data, and the teacher wrote the data of the circumference and diameter of the circle on the blackboard. Then, the teacher asked everyone to work out a round week in the draft book.
Divide the length by the quotient of its diameter, and then write this data on the blackboard. At this time, everyone found that the circumference of each circle is always a little more than three times the diameter, which is an infinite acyclic decimal. Teacher Jane smiled and said, "Classmate.
Ladies and gentlemen, this infinite circulating decimal is actually a constant value. We call it pi, which is expressed by the letter "π". When calculating the perimeter, we usually take 3, 14. Then, know the pi, and know the circumference and diameter of the circle.
We can find two formulas for a circle: "c=πd or c=2πr". "The students suddenly realized that the original circumference is the diameter multiplied by pi. It's that simple! Everyone gets it. "Ding Rinrin!
The bell rang, and the students learned a new knowledge in this class: pi.
How interesting this interesting math class is! Let everyone learn mathematics in practice, and at the same time let me realize the wonderful and interesting mathematics. I fell in love with it.