First-and second-grade pupils in math diary

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.

Math diary II, 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 simple, that is, when the pointer turns to the odd or even grid, the next number must be added. If it adds up to an odd number, I win; If the total is even, 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!