Math diary six articles, a second-grade pupil.
1. math diary, a second-grade pupil.
Recently, studying three-dimensional graphics also made me think about a mathematical problem: why do tea cans have to be designed in a cylindrical shape? What is this for? Is it for beauty or courtesy? I thought about it carefully, but I didn't know anything. One afternoon, a guest came to my house, and my father asked me to pour tea for my uncle. Seeing canned tea, I suddenly had a brainwave and asked my uncle, "Do you only know why canned tea should be designed as a cylinder?" My uncle asked me, "Why do you think?"
I racked my brains and couldn't think of any way, but I didn't want my uncle to look down on me, and it didn't help.
Uncle looked at me puzzled and said with a smile; "You might as well start with a few figures with the same perimeter and circle area." After listening to his words, I suddenly realized. The cylinder used in the teapot can not only hold more tea leaves, but also save materials. I've learned that sometimes math problems in life can only be solved by contacting the knowledge in textbooks.
2. math diary, a second-grade pupil.
One day, I finished my homework early, and my mother came up to me and said kindly, "Son, have you finished your homework?" I nodded my head. "Then let's play a game!" Mother brought a round cardboard and fixed a rotatable pointer in the center of the cardboard with a nail. Then divide the circular cardboard into 24 grids on average, and write 1-24 numbers in each grid. "Mom, what are the rules of this game? Say it quickly! " I said I was in a hurry. "The rules of the game are very simple, that is, when the pointer turns to an odd or even grid, the next number must be added. If it adds up to an odd number, I win; if it adds up to an even number, you win. " Mom said with a sly smile.
I think this game is too simple. I have played it for more than ten times in a row. However, mom always wins. I thought hard and never thought of it. Mom smiled and asked, "Why does it add up to an odd number every time?" So, I racked my brains to think, and finally thought of it, and shouted: "Mom, you are so cunning. No matter which number you go to, adding the next number equals the singular number. That is, odd plus even equals odd. If the pointer points to an odd grid, then the next number must be even; If the pointer points to an even cell, then the next cell must be an odd cell. So no matter which grid you go to, the total number is odd. Mom, you won with this rule. "
In the world of mathematics, there are many wonderful laws everywhere. As long as we learn mathematics well and make good use of it, we can become small experts in mathematics!
3. math diary, a second-grade pupil.
One morning, the sun was shining and there were no clouds in Wan Li. I was walking in the street after buying breakfast when I suddenly saw many people around a table. I ran over and saw that it was a lottery, and I felt bored when I saw it. I wanted to leave in a hurry, but when I heard someone say that 50 yuan won the grand prize, I immediately became interested. Ask the shopkeeper what the rules of the game are. The shopkeeper said, "Here are 24 cards, 12 is 5, and 12 is 10. Grab the 12 card once. If the total number is 60, you can win the 50 yuan Prize. " I quickly took out 5 yuan and started to touch the cards, but 12 times didn't win the prize. When I got home, I thought it over. The total number is 60, so the card of 12 must be 5, but it is 5 every time. It costs at least 6 yuan money to catch a 12 five for the first time, but in case the number of cards caught is 10 or the sum of the two is the same, it means that it costs a lot of money to catch as many times as possible.
I understood the mystery below and ran to the original store. The manager was gone, and I couldn't find him anymore.
4. math diary, a second-grade pupil.
Today, my father and I went to the supermarket. Dad took me to the street corner where vegetables were sold. We bought 2 Jin of cucumber, 1 Jin of tomato and 2 Jin of my favorite potato. On the way back, my father asked me, "There are just four cucumbers. There are three of us, but my mother went to Jinan. How many do we each eat? " Recalling the division I learned before, I said, "4÷2=2, everyone eats two." Dad asked again, "These four cucumbers cost 2 3 yuan cents each. How much is each cucumber? " I thought about it and said, "3 yuan's 2 angles are 32 angles, and 32÷4=8, each of which is 8 angles." Dad nodded, smiled and said, "You're right!" Today, I am so happy! I bought my favorite vegetables and learned math knowledge. It's killing two birds with one stone!
5. math diary, a second-grade pupil.
Do homework 1-9 in the math book today. After finishing, do it for the first time and give it to my mother for signature. My mother said that if I didn't finish it, I would check it and make it up. Second, give it to mom for signature. Mom said, I haven't finished it yet. Check it again and make it up. Sign my mother's name for the third time. My mother was angry and said loudly that it wasn't over yet. Please check it carefully and make it up. The fourth time, I checked carefully from the first question to make sure there were no missing questions before handing them over to my mother for signature. Fortunately, I finally passed the test. After my mother signed it, she severely criticized me, saying that my heart is thicker than the pier of Jiubao overpass, and I must form the habit of self-checking homework in the future, otherwise I will get good grades in the exam and fail if I am not careful.
6. math diary, a second-grade pupil.
Today we have a mid-term math exam, and I thought to myself: I must refuel and take the exam 100. After the teacher handed out the test paper, he began to look at the topic and finished the first question. I think this question is particularly simple, because I am still full of confidence in my oral expression ability. Doing it, it's done before you know it. I feel that I did well in the exam, and intellectual surfing is a piece of cake, but I still don't believe I can get 100. I checked it from beginning to end, and found no problems, so I handed in my paper hopefully. At noon the next day, the teacher handed out the test paper, and I was particularly nervous. I also heard the sound of my heartbeat, and finally heard my name. When I saw it, it turned out to be 100+ 10, and I was dancing with joy. I thought to myself: Mom will be very happy and will give me a reward.