Math diary's composition

The day is about to pass, and there must be a lot of feelings. Take action at once and keep a diary. What are the novelty and richness of diary writing? The following are 9 essays on math diary that I compiled for you, hoping to help you.

Math diary Composition 1 I saw an article "math diary of Boiling Sheep" in the second-grade education MMS [Mathematical Paradise], and I thought it was quite good. It happened that my son had just learned cm of knowledge and read it to his son.

In the first week of school, Grandpa Slow Sheep taught the lamb two units of length: centimeter and meter. On the weekend, Grandpa Slow Sheep gave the lambs a math homework: write an article about math diary's understanding of centimeters and meters. After arriving at school on Monday, Grandpa Slow Sheep asked Boiling Sheep to stand up and read his math diary to everyone. Boiling sheep read: "On Saturday morning, at the urging of my mother, I reluctantly climbed out of the 2 cm long bed, washed my face first, and then picked up a toothbrush about 15 meters long to brush my teeth." My mother prepared breakfast for me. I sit at a table about 1 cm wide and have breakfast. I saw my mother cut the cucumber into 5-meter-long pieces ... "I haven't finished reading the Diary of Boiling Sheep, and the lambs have laughed so hard that even Grandpa Slow Sheep can't help laughing."

After reading it, I asked my son, "Do you know why everyone laughs so hard?"

The son was also amused and laughed: "All wrong!"

"Then tell me, what's the matter?"

The son stretched out his index finger and said, "The bed is 2 cm wrong, the toothbrush is wrong 15 m, the dining table is wrong 1 cm, and the cucumber is wrong 5 m.. 1 cm is the width of an index finger; 1 m is equal to 100 cm. "

"My son is much more careful than boiling sheep. Please help me to revise this diary! "

"The bed should be 2 meters, the toothbrush 15 cm, the dining table 1 m and the cucumber 5 cm."

"Look at the revised diary together!"

"On Saturday morning, at the urging of my mother, I reluctantly got out of the 2-meter-long bed, washed my face first, and then picked up a toothbrush about 15 cm long to brush my teeth. My mother prepared breakfast for me. I sit at a table about 1 m wide and have breakfast. I saw my mother cut the cucumber into 5 cm long pieces ... "

MMS also tells us some common sense, and I will read it to my son: "Your feet are about10cm; Spread your arms, and the distance between them is about 1 m; The building on the first floor is about 3 meters high. To judge whether the length unit of an object is centimeters or meters, we must first think of the actual lengths of 1 cm and 1 meter, and then compare them with the width of the index finger, the length of one foot, the distance between two arms or the height of the building, so that it is easy to find the correct answer. "

Thanks to the education mm for providing us with interesting knowledge, and also thanks to the author for his wonderful sharing.

Math diary Composition 2 20xx It was cloudy on Monday, March 8th.

Er yi ban ma Tian

My mother bought nine apples today. My mother said, "Martin, how many apples did you give us for three?" I said, "All right!" I gave my father an apple first, and then I gave my mother an apple. I took an apple. Then I gave my father an apple, gave my mother an apple, and I took another apple. I see there are three apples left. I said, "Of course it's one person and three." Mom said, "Martin is great!" " I asked my mother, "Do you know what this is called?" Mom said, "I don't know." I said, "It's called an average score." Mom said, "Martin knows more than mom now!" " "After listening to my mother, I jumped three feet high with joy!

This is written by Martin himself, and here is what I helped him modify. I hope my colleagues will give me more valuable advice!

Today, my mother bought nine apples and said to me with a smile, "How do you and your parents share these apples?" I remembered the average knowledge we learned today and said confidently, "Let me share it."

I first gave one to each of my parents, and then put one in front of me, learning from the teacher's tone and saying, "What about a person? A person is impartial and has no opinion!" " Mom and dad looked at me, sipping their mouths and laughing, waiting for me to continue to divide. In this way, one for each person until nine apples are divided.

"Do you know what this is called?" Today, I am addicted to my teacher and asked my mother seriously. Mom shook her head like a wave drum and said she didn't know. I said, "To be honest, it's called an average score." Mother said, "Martin knows more than his mother now." Teacher Ma is really amazing! " "After listening to my mother, I jumped three feet high with joy!

In class, I want to listen carefully, learn everything the teacher says and be my mother's little teacher!

Math diary Composition 3 One night long ago, Grandpa's home with a math book was really lively! Because grandpa's two children-positive and negative-had a quarrel. They are arguing about who is more useful.

My brother spoke first: "I have many uses. I am everywhere in my life." For example, people use me; The accountant is using me; I'm also on the thermometer. In a word, I am indispensable in life. People like me. I have the greatest credit. "My brother said negatively," I have many uses. For example, I will be used when the thermometer indicates a few degrees below zero, and I will be used when the settlement indicates a loss. "You can't live without me. My credit is not small. " Positive numbers say, "Although you are negative in many places in your life, people don't like you in many places, such as profit and loss problem, who got hurt in the mall. Merchants like me because I represent profit, that is, how much money I have earned, and you represent loss, that is, how much money I have lost. So people don't like you. So I am more useful than you. " The negative number said, "Although sometimes people don't like me, there will be a lot of inconvenience in life without me. People will not be able to record numbers below zero. This is very inconvenient. Therefore, I have the greatest credit. " The two brothers quarreled so much that they even fought. At this moment, Grandpa Math Book spoke. "son! Stop arguing, you each have your own uses, and no one can live without anyone. You should live in harmony and make contributions to mankind. In this way, people will really like you and you can really play your role. " Hearing this, the brothers both thought that Grandpa was right. From then on, they never quarreled again. They worked hard together to serve mankind and became good friends of mankind.

Math diary Composition 4 Mom and Dad went to work today, and grandparents went out to eat. I have been to "home alone" once. So I went to the vegetable market alone to buy food.

When I came to the largest vegetable market in Xiongzhenlou, I couldn't help sneezing as soon as I entered the door. I walked in and saw a vegetable stall selling celery. He bought 1.5 yuan a catty of celery here. Seeing that I was a child, the stall owner said, "Little friend, are you going shopping alone?" I said, "Sure, can this celery be cheaper?" The stall owner smiled and said to me, "Look at you as a child, I will give you a 20% discount." In my mind, I bought 1.2 yuan a catty after the celery here was discounted.

I walked around again and saw a booth selling celery. Curiously, I went to the stall owner and asked, "Uncle, how much do you sell celery here?" The stall owner tidied up the food and came up to me and said, "Little friend, the celery I have here is very cheap. 1.8 yuan. How about I give you 50% discount? " As soon as I figured in my mind that the celery was a catty of 0.9 yuan after being folded in half, I bought it immediately.

I bought a lot of vegetables today: celery, bamboo shoots, mushrooms, tofu and pork. I am very happy and hope to have the opportunity to buy food by myself.

Math diary Composition 5 Today, my parents and I went shopping in the supermarket. We came to an empty trust-mart where there were many goods with different quantities and prices. My mother wanted to take this opportunity to test my ability, so she said, if my father wants to buy four bottles of plum wine, how much will it cost him for each bottle of 68 yuan? I proudly said: This is simple, as long as 4×68≈280 yuan. Mom asked again: That Lotte Chocolate Pie is a box 12. 5 yuan, how much do you need for three boxes? I said to my mother, 12. 5 12。 5, calculate first1212 = 24,0. 5 0。 5 = 1, and then 24 1 = 25 12. 5=37。 5 yuan. Mom asked me: So how much did the plum wine and Cleopatra cost? I said: about 3 10 yuan.

Mom said with a smile, you are quite smart, but if you get the last question right, you can buy what you want. I said yes in one bite. Mom asked: if I want to buy a bag of bread, it will be 7. 5 yuan, cheese is 19. 5 yuan, milk 43. 5 yuan, chocolate 56 yuan, how much is it altogether? Plus my father's plum wine and chocolate pie, I brought 500 yuan. Is this enough? I replied: 7 first. 5 19。 5 = 27 yuan, and then calculate 27 43. 5=70。 5 yuan, more than 70. 5 56= 126。 5 yuan and dad's plum wine is 68× 4 = 272 yuan, and chocolate pie is 12. 5×3=37。 Five dollars, and finally put 37. 5 272 126。 5 = 436 yuan, and then compare 500 yuan and 436 yuan, who is bigger or smaller, because 500 yuan is bigger than 436 yuan, so the final answer is: 500 yuan is enough. Mom smiled and said, yes, you can choose what you want to buy. I chose a box of fruit candy.

I'm really happy today. I can buy what I want and learn my favorite arithmetic.

One day, my mother asked me, "Do you know which is heavier, a cubic meter of cotton or a cubic meter of iron?" "Of course it's heavy!" I answered without thinking, and my mother smiled and continued to ask, "Who is heavier, a square meter of cotton or a square meter of iron?" "Iron is heavier than cotton!" I said without hesitation, and my mother continued, "Which is heavier, one kilogram of cotton or one kilogram of iron?" "It's also iron!" "Ha ha, is it?" Mother asked, "Why?"

I froze and thought, yeah, what's wrong? Will iron be heavier than cotton? So I fell into thinking and suddenly realized after thinking. I just thought that iron would be heavier than cotton, and I never thought that it would be as heavy under any circumstances. A kilo of cotton is as heavy as a kilo of iron. Alas, I answered the question incorrectly. No wonder my mother always tests me. Think it over before you answer in the future, it won't be so ugly. This incident has benefited me a lot.

Math diary composition 7 February 14 Saturday sunny

Today is another sunny day. I was wandering in the street when I suddenly saw a lot of people gathered not far away. I ran for a year, and the result was a prize-winning game. "Hum, what's fun about winning the prize?" I was bored when the person next to me quickly said, "It's not fun to grab the prize, but there is a big prize that can attract people." I asked eagerly, "What is it!" "50 yuan money." The man with big eyes said. I'm very excited to hear that. "I have to try anything for such an attractive prize." Then I asked the shopkeeper how to catch it. The shopkeeper said, "This is 24 Mahjong, and it says 12 5, 12 10. You can only catch 12 mahjong at a time. If the total number of 12 mahjong targets is 60, then you can win the 50 yuan Prize. " Without rolling up my sleeves, I took out 5 yuan money from my pocket and gave it to the shopkeeper.

Although I won 10 times, I still didn't win the grand prize.

When I got home, I thought about it and felt something was wrong. I think, to get 60 points, all 12 mahjong should be marked with 5. In the best case, the first 1 second catch 1 5, the second catch of two 5 s and the third catch of three 5 s will cost at least 6 yuan money. But what if the target number of mahjong is 10 or the sum of the two is the same, how many times will it cost?

Finally, after some consideration, I finally figured it out. I rushed to the street to look for an account, but I ran away without a trace.

Saturday, February 28th is fine.

When I read the newspaper today, I saw such a topic: Find the surface area of a cone.

A cone, the diameter of the bottom surface is 6 meters, and the length from the apex of the cone to any point on the circumference of the bottom surface is 5 meters. Find the surface area of this cone.

Although I have never learned to calculate the surface area of a cone, I have learned the surface area of a cylinder. By solving the surface area of cylinder, I know that the surface area of cylinder is equal to one side plus two bottom areas, while the surface area of cone is one lateral area plus one bottom area, and the side is a sector. Although I haven't studied it, I have checked the data and know that the area of a sector is: the area of a sector = arc length × circle radius × 1/2. The topic has told us that the length from the apex of the cone to any point on the circumference of the bottom surface is 5m, while the arc length is 3. 14×6= 18.84 (m), and the sector area is18.84× 5×1/2 = 47./kloc.

Mathematics is the gymnastics of thinking. As long as we study hard and think hard, we will certainly overcome the problems and embark on the road to success!

Tuesday, 2 March

Every time I go to Tomb-Sweeping Day, there will be a sea of people on the giant mountain, so some swindlers come up with some deceptive tricks, such as gambling on something on a plate.

Prop is very simple, draw a big circle on a board, and fix a rotatable pointer in the center of the big circle with a nail. The great circle is divided into 24 equal squares, and the needles in the squares can rotate. The box says 1-24 equal numbers, which are worthless in the odd box, but almost all even numbers are valuable.

The gameplay is also very simple. Set the pointer to 1 first, then you dial the pointer again, and the pointer will start to rotate and finally stop in a grid. Then press the number marked on the grid where the pointer is located and dial the pointer again. N- 1 grid, where n is the number marked on the grid. This is just a little math game. In fact, no matter which box you dial, you can only lose money, not make money. Because when the pointer turns to the odd cell, the number of cells dialed is odd-1= even, and odd+even is only equal to odd, so it is impossible to turn to the even cell and nothing valuable can be obtained. If the pointer turns to an even cell, the number of cells dialed is even-1= odd and odd.

Number+even number = odd number, and you haven't got anything of value yet.

Friday May 12

Calculate wages

At noon, my father came back from work, humming a ditty, and happily stepped into the house. I greeted him and asked, "Dad, what's so happy today?" Dad said, "I got a raise this month." I asked, "How much salary do you get now?" Dad thought for a moment, smiled and said, "My salary is higher than your mother's. Our monthly salary adds up to 2800, and the monthly salary difference is 100. How much do you think I get a month? "

After listening to my father's words, I began to draw line drawings on paper to help me understand:

Through observation and thinking, I quickly worked out the answer and told my father. First of all, mom's salary is as much as dad's, so mom and dad's monthly salary is (2800+ 100)=2900 yuan, and then the total monthly salary is divided into two parts, and 1 part is dad's monthly salary. The formula is: (2800+ 100)÷2= 1450 yuan.

Dad listened and nodded with satisfaction. At this time, my mother, who was cooking, said to me, "Do you have any other methods?" "Is there any other way?" I said in surprise. I stopped to observe and think curiously. I found that the key to this problem is to find out who is the standard. Different standards have different methods. So, I have a second method: taking mom's salary as the standard, assuming mom and dad's salary is the same, then the sum of their monthly salary is (2800- 100)=2700 yuan, and then divide the sum of monthly salary into two parts on average. 1 part is mom's monthly salary, and finally it is more than mom's 100. The formula is (2800-100) ÷ 2+100 =1450 yuan.

After listening to the second method I introduced, mom and dad both laughed. ...

It will be sunny on Wednesday March 24th.

The electric fan factory plans to produce 1600 electric fans within 20 days. After five days of production, due to the improvement of technology, the work efficiency has increased by 25%. How many days will it take to complete this task?

Analysis: This problem can be solved by direct proportion method through transformation. If the original efficiency is "1", then the actual efficiency is (1+25%)=5/4, and the ratio of actual efficiency to original efficiency is 5/4: 1 = 5: 4, because efficiency is inversely proportional to time.

It will take x days to complete this plan.

4∶5 = X∶20-5

5X=4× 15

X= 12

A: It takes 12 days to complete the plan.

Saturday, March 27th is fine.

I was bored today, so I took out a math newspaper, and suddenly a very special topic attracted me.

[Title] There is a rectangular iron sheet, which can be made into a cylinder by cutting off the shadow in the picture. The radius of the bottom of this cylinder is 2 decimeters, so what is the area of the original rectangular iron sheet?

[Analysis and Problem Solving] Look carefully at the right. The width of the shadow rectangle can't be the circumference of the bottom of the cylinder, so the circumference of the bottom of the cylinder is the length of the shadow rectangle. In addition, we can also find the width of the rectangular iron sheet, that is, the height of the cylinder is twice the diameter of the cylinder bottom, and the diameter of the cylinder bottom+the perimeter of the cylinder bottom is equal to the length of the rectangular iron sheet. Therefore, the length of rectangular iron sheet is 2× 2+2× 3.14× 2 =16.56 (decimeter) and the width is 2×2×2=8 (decimeter). The area of the original rectangular iron sheet is 16.56×8= 132.48 (decimeter).

Saturday, March 27th is fine.

Think about problems in combination with reality.

Think about it, where is he wrong?

[Title] There are two cylindrical wooden columns in a hall. The diameter of the bottom of the wooden column is 0.6m, and the height of the column is 6m. If you want to paint their surface, how many square meters is the painted part?

After reading this question, Xiao Qiang felt very simple. He quickly listed the formula and worked out how many square meters the paint area was.

3.14× (0.6÷ 2 )× (0.6÷ 2)+3.14× 0.6× 6× 2 = 23.7384 (square meter). A careful analysis of the meaning of the problem reveals that Xiao Qiang's idea is completely wrong, and the reason for the mistake is that he didn't think about the problem in combination with reality. Although the wooden column is cylindrical, as far as practical problems are concerned, the painted part does not include the upper bottom surface and the lower bottom surface. Therefore, it is necessary to draw part of the area to find the side area of these two cylindrical wooden columns. The formula should be: 3. 14×0.6×6×2=22.608 (square meter). A: The area of the painted part is 22.608 square meters.

Monday, June 9th, sunny to cloudy.

After school in the afternoon, the class teacher gave us a homework assignment, asking everyone to find a way to measure the volume of disposable chopsticks and record the measurement process in the form of math diary. On the surface, this assignment is a mathematical practice, but in fact it may have a deeper meaning, because the use of disposable chopsticks is related to environmental protection.

As soon as I got home, I sat quietly at my desk and thought about it. Disposable chopsticks are irregular three-dimensional figures. How do we measure its volume? I reasoned, scratching my head for a while, shaking my head for a while ... finally, I got something. I can put disposable chopsticks in a container full of water, so that the water in the container will overflow. Isn't the amount of splashing water as big as chopsticks? But chopsticks are lighter than water and will float on the water. What shall we do? Can you fix chopsticks with stones or tape or something? I think it should be possible, but these methods are too troublesome to measure. If only there were a simpler way! After thinking hard, I finally smiled proudly.

June 10 will be fine on Tuesday.

I went to the restaurant to buy a box lunch at noon today, and specially asked for several pairs of disposable chopsticks to prepare for the experiment.

When I got home, I was really excited at the thought of doing the experiment, but I was a little scared. I don't want the first plan to be eliminated as soon as it comes out. In order to verify the correctness of the experimental scheme, I specially measured the length (20cm), thickness (0.35cm) and width (1.6cm and 0.8cm respectively) at both ends of chopsticks. Because disposable chopsticks are similar to trapezoid, I use the formula to calculate the volume of trapezoid to calculate the volume of chopsticks. According to the calculation results, the volume of disposable chopsticks is about 8.4 cubic centimeters. If the results measured in the experiment are similar to those calculated by me, it means that my experiment has been successful, otherwise, I have to find another way. I'm about to start the experiment, but the experimental equipment is not enough, so I can only wait until tomorrow.

June 1 1 Wednesday is fine.

The moment of hope has finally arrived. After school, I trotted home and put down my schoolbag. I can't wait to pick up the beaker my father borrowed from the company. After being filled with water, carefully put the beaker into the basin to ensure that the water in the beaker does not leak. Then, I carved a mark on the chopsticks with a knife and divided it into two parts. This mark is the dividing line between the two parts of chopsticks. I want to measure the chopsticks twice.

When the experiment started, my heart was pounding with nervousness, and my hands holding chopsticks were shaking from time to time, but I tried my best to control this excitement. I slowly insert chopsticks into the beaker and try not to shake them, otherwise the water will overflow too much and the measurement result will be inaccurate. After inserting a part of chopsticks into the beaker for the first time, I saw that some of the water in the beaker overflowed into the basin. After the beaker is filled with water, another part of the chopsticks is inserted into it. Finally, I poured the water overflowing from the basin into another beaker with scales twice, thus obtaining the volume of chopsticks.

As a result, I failed. The size of chopsticks measured in the experiment is only 3 cubic centimeters, which is far from the size of chopsticks calculated by me. At first, I still didn't believe it. After repeated thinking, I finally understood the reason for my failure. It turns out that the diameter of the beaker is too large, even if the beaker is not filled with water, people's vision will think it is full, while the size of chopsticks is too small and the scale of the beaker is too large, which leads to the deviation of the experimental results. Therefore, I must improve my experimental method. Believe that I will succeed. Isn't failure the mother of success?

June 12 Thursday is fine.

Since the first experiment failed, I have been trying to improve it, but I just can't think of a simple and feasible way. At noon that day, mom and dad didn't cook, so we decided to eat out.

After ordering in the restaurant, in order not to disturb my waiting, my mother specially ordered a glass of juice. As soon as the juice came, I took a few swigs. My mother told me to drink less juice for fear that I would lose my appetite after drinking it. Before the food was served, I felt that I had nothing to do, so I thought of blowing bubbles, so I picked up the straw in the juice bottle and blew a few breaths at the water. For a moment, I thought that when I took the straw in the cup just now, the water level dropped a little, and suddenly I had an idea. I was so happy that my appetite increased greatly. I ate several bowls of rice today, which is not enough.

It will be fine on Friday, June 13.

At noon today, in order to measure the size of chopsticks more accurately, I asked my father to take a slender measuring cylinder from the chemistry room. The scale unit is smaller, and each unit is only 1 cubic centimeter. At this point, I seem to feel victory beckoning to me. I really have everything except hands-on experiments.

First of all, I drew a dividing line on disposable chopsticks with a pencil, divided the chopsticks into two sections evenly, and soaked them in water to avoid washing them when measuring. Then, insert the chopsticks into the measuring cylinder, drop water into the measuring cylinder with a dropper, let the water in the measuring cylinder rise to the dividing line of the chopsticks, take the chopsticks out of the measuring cylinder after recording the water level scale (38 ml), and then record the water level scale (34.5 ml) in the measuring cylinder. The difference between the two water level gauges is the volume of this part of chopsticks, which is 3.5 cubic centimeters. In the same way, I measured the volume of the other part of the chopsticks to be 5 cubic centimeters. When the two measurements are added together, the volume of the chopsticks is 8.5 cubic centimeters. When I got the result, I cried excitedly. How proud and proud I am at this time!

Then, according to the situation that each person uses three pairs every day, I calculated the disposable chopsticks consumption of our school (1500 people) and the whole country (1200 million people) for one year, which are 13.96 cubic meters and169000 cubic meters respectively. The result surprised me. What a pity to waste so many wooden disposable chopsticks every year! I hereby appeal to the students at school, no! It is the people of the whole country, and it is not! Everyone in the world should stop using disposable chopsticks. Only in this way can we protect our forest resources, make our earth environment better and let everyone on the earth breathe clean and fresh air.

At noon today, I was doing my math summer homework. Writing, unfortunately, I have a problem. I thought about it for a long time, but I couldn't figure out a way. The question is this:

There is a cuboid, the product of the front and the upper two areas is 209 square centimeters, and the length, width and height are prime numbers. Find its volume.

I saw it and thought: this question is really difficult! Only knowing the product of two surface areas, the volume must also know the length, width and height, but there is no hint at all. How does this start?

Just as I was scratching my head, a colleague of my mother came. He taught me to use the idea of equation to solve it first, but I am not very familiar with this method of equation. So, he taught me another way: list the numbers first, and then exclude them one by one. First, we listed a lot of numbers according to the requirements of the topic, such as: 3, 5, 7, 1 1, and then we began to exclude them, and then we found that only1and 19 were left. At this time, I thought: one of these two numbers is the length of the common side of the front of the cuboid in the question; One is the front of the cuboid, and the other is the division of the previous one.

Sum of side lengths (all lengths are prime numbers). So, I began to tell which number these two numbers were.

The final result is 374 cubic centimeters. My formula is: 209 =119 = 2+171× 2×17 = 374 (cubic centimeter).

Later, I checked this problem with what I learned this semester: prime factor decomposition, and the results are exactly the same.

I am happier than anyone to solve this problem. I also understand the truth that mathematics is full of mysteries, waiting for us to explore.

I met another math problem today, and it took me a lot of effort to solve it. The topic is: there are 30 birds in two trees, and 4 birds fly away from the second tree first. At this time, tree A flew to tree B with three birds, and the birds on the two trees were just equal. How many birds are there in each tree?

Math diary Composition 8 I am full of joy, because I will have enough fun with my three sisters in Jinhua! Just then, the bus came! I quickly ran into the car and grabbed a seat to sit down! "Selling tickets! Tickets are on sale. " A crisp cry rushed into my ears, and an amiable aunt came up to me step by step. I took out my money and said, "Four people paid together to go to Zhejiang Middle School to buy books!" I don't know if my aunt is wrong! Or what? I only took the money from 8 yuan! And after receiving the money, he turned and left! So, I shouted: "Aunt, you took two yuan less!" " Aunt, turn around at once! I saw him coming up to me with a shy face and saying, "Little girl, I haven't miscalculated the money several times all year round. It's rare. I won't tell you if I do it several times!" " You are the first to tell me! "Say that finish, she took two dollars from me again, and boasted," Little girl, you! Really honest! " After saying what she said, my heart was filled with joy!

It seems that the decimal multiplication I learned is still very useful in our life! Of course, we should be honest!

Math diary Composition 9 These days, I have been thinking of another method to calculate the volume of a cylinder. Based on my feeling, I have listed such a formula: diameter × diameter × height ×3. 14÷4。

After coming home from school, I began to prove whether this formula was correct. I tried it, and the solution in the textbook is exactly the same as my solution for calculating the volume of a cylinder. I have tried many times, and the result is the same.

I feel very distressed. What do I mean by this solution? After some thinking and proof, I found that a cylinder is regarded as a cube with equal diameter and height. Then calculate the volume of the cube, and according to the ratio of the cylinder to the cube, it is: 3. 14: 4 becomes the volume of a cylinder.

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