Number one: I want to buy chocolate.
I just finished my homework this evening. At this moment, the doorbell rang. I am very happy, because I know this is my mother's reward. My mother hasn't talked to me for a long time.
After the doorbell rang for five seconds, I quickly ran out of my desk to open the door. As soon as my mother entered the room, she said to me, "Hey, I brought back 1 box of Japanese chocolate!" I immediately cheered: "Yes, it's very kind of mom. Come, give it to me! " "Mom said," mom is not good. I can't just give you chocolate. You must answer my question. "After hearing this, I thought to myself: I am not afraid if you want to test me again!
Mom has a problem: I think it's a matter of reasoning this time. Xiaoming said to Xiaodong yesterday: "Yesterday, there were 10 students in our family. My mother took out a bag of sweets, which contained 54 sweets, and distributed them to small guests, but the number of each person was different. The most frequent one is 10. " Hearing this, Xiaodong immediately said, "You are lying! You lie! " I asked you why Xiaodong said Xiaoming lied. At this moment, I had a brainwave and thought that I had learned "simple reasoning" before. This question is different. I began to calculate: the most one got 10, so there can't be duplicate numbers. Let's assume that the first one gets 65,438+0 candy, the second one gets 2 candy ... and the tenth one gets 10 candy. Xiao Ming is lying, because he said that the bag of candy has 54 pieces, but actually one person wants 55 pieces, so Xiao Ming is lying.
I told my mother what I thought just now. My mother said I was smart, so she gave me this favorite Japanese chocolate. I think mathematics is really everywhere. Even I have to use math to get these chocolates. I got it, which is the crystallization of my efforts, hee hee!
Teacher's comment: This diary shows that the author is a brain interactive body and has a persistent spirit through a simple story about Olympic Mathematics.
Chapter 2: Dad's Magic
Tonight, my father mysteriously said to me, "Silver, I can do magic.". Do you believe it? " I can't wait to ask; "What? Do you know how to operate it? What massage is it? " "The magic is this: when you open a book, I can use magic to tell which side is an even page and which side is an odd page." Dad said proudly. Well, I don't believe it. I asked my father to demonstrate the massage on the spot.
I picked up a book and flipped through it quickly. When my father called "stop", I stopped turning the pages. Dad said with a slight air; "There are even pages on the left and odd pages on the right. I calculated, hey, awesome! Dad guessed right. Not convinced, I tried again and the result was still the same. I asked my father inexplicably, "Dad, how did you guess right?" Do you really have magic? "Dad answered me with a smile;" No, I didn't do it. According to the rule that there are even pages on the left and odd pages on the right of the book, I guessed right.
Today, I feel very happy because I have learned another math rule. Math is really interesting!
Teacher's comment: In this article, the little author expounds a mathematical law in vivid language: there are even pages on the left side of the book and odd pages on the right side of the book. Although the article is not long, the language is vivid and makes people shine. The context is clear, the truth is revealed at the end, and it is naturally revealed.
Article 3: Shopping.
On Saturday, my mother took me to the mall and bought me many delicious snacks and the most fashionable sportswear. Only then did we return home happily.
"Dad, we are back." I shouted, throwing my tracksuit on the sofa and lying down. "I'm exhausted!" "
"How much did you spend on sportswear today?" Dad asked with a smile.
"Then test you!" I said confidently.
"Yes, if you can't answer, treat us to a buffet tonight." Mom said.
"Great, I love to eat buffet. My question will definitely beat you. " I am happy to say.
"Well, please listen to the question. Today, I bought sportswear, pants 128 yuan, and the top is twice less than the pants. In 78 yuan, a pair of sports shoes is three times more expensive than a sports coat. 53 yuan, please ask dad to calculate, how much did I spend on sportswear and sports shoes today? "
Hearing this, my father thought for a while, and his head got bigger. He said shyly, "You'd better find out what happened two or three times. If it's right, I'll treat you to a buffet. "
"Well, the price of trousers is known as 128 yuan, and the coat is less than twice that of trousers, 78 yuan. The coat price is X yuan, X+78 = 2× 128, X = 256-78, X = 178, so the coat is 178 yuan. The price of shoes is more than three times that of coats, 53 yuan. Coats have been found in 178 yuan, so let's assume that the price of shoes is y yuan, y-53 = 3x178, Y = 534+53, Y = 587, and the price of shoes is 587 yuan. 128+ 178+587 = 893 yuan, so my sportswear and sneakers cost 893 yuan. "
"My daughter is still smart, please go to the buffet!" Mom said happily to dad.
Today is my happiest day. Just learn math well!
Chapter 4: Heart calculation method
I have seen such a news that people's hearts are as big as fists. Today I will measure my fist and know how big my heart is. But our fists are irregular objects. How should we measure them? I thought about it, and finally came up with a good way, that is, using water to measure, because in our practice class, we use water to hybridize potatoes!
I found a hollow cylinder with a radius of 4 cm and a height of 9 cm. I filled it with water, then put my fist in it, and the water immediately rose, and then I took my fist out. The water surface immediately dropped from 9 cm to 4 cm. I calculated the volume of my fist with the square of 4× 3. 14× (9-4), which is about 25 1 cubic cm.
After I measured the volume of my fist, I was still not sure whether it was correct, so I used another experiment to prove that it was 250 cubic centimeters, which was not much different from the last time.
This experiment tells me that as long as you dare to explore, you will get unexpected gains. "Practice makes true knowledge!"
Chapter 5: Wonderful Mathematics
In life, mathematics is everywhere. For example: buy food! Buy stationery! Measuring cloth, etc. , all need to use mathematics.
This semester, the teacher taught a new knowledge, that is, the multiplication and division of decimals. This knowledge helps me a lot!
Last night, my mother went to buy oranges together. A kilo of oranges 1.8 yuan. My mother bought 4.5 kg and should pay 8. 1 yuan. But the clerk was careless and didn't know how to calculate it, so it became 9 yuan money. Fortunately, this semester, I used the knowledge of Protestantism, and after doing a calculation in my mind, I immediately corrected the salesman's mistake.
Not only did my aunt, the shop assistant, praise me for my cleverness and my ability to multiply and divide decimals in such a small city, but my mother also praised me for saving her 0.9 yuan on the way home, and the knowledge I learned can be applied in my life.
Yes! If you don't learn this math well, it's not only 0.9 yuan that will lose, but also hundreds, thousands or even hundreds of millions!