During May Day, my mother and I went to the mall to buy clothes. However, I think the price there is very strange: saying "buy 100, get 100" means there is no money?
Mother said, "Silly daughter, how can you not use money?"
I said, "Because it says buy 100, get 100, which means 100- 100=0, so no money is needed!"
Mom said, "that's how you calculate." If so, everything in the mall is free, and many guests will come. This mall will lose a lot. "
Mom also said that you only need 50 yuan to buy 100 and get 100, you know?
After listening to my mother's analysis, I still don't understand. Why? It seems that I still have to go to the shopping mall to make a serious investigation or consult Ceng Laoshi to see what she has, because I know there is still a lot of math knowledge I haven't understood yet.
With a happy mood, I came to the school to ask Ceng Laoshi a math question. Ceng Laoshi said, "In fact, some of them exceeded 65,438+000. For example,109,200, 189 or above ... "
The teacher added, "If the amount exceeds 100 yuan, you will get a coupon of 100 yuan. Customers still have to spend enough money 100 yuan to get the coupons. Not as free as you said. " Ceng Laoshi praised my questions and welcomed me to ask more questions in the future.
Math diary, the fourth grade of primary school: (doing homework)
On Saturday afternoon, when I finished my homework and had nothing to do, my mother gave me a question: "Do you know the characteristics of multiples of 2?" As soon as I heard it, I immediately replied: they are all even numbers. "What are their characteristics?" Mom asked again. "Their units are all 0, 2, 4, 6, 8." Mom said, "You are really something. Then do you know the multiple of 4 and know the characteristics? " Now you have me stumped.
So, I found some multiples of 4 and found that their units are also 0, 2, 4, 6, 8, so I told my mother this rule. But my mother casually said a number, which overturned my discovery. Mom told me to keep watching, but I couldn't find it left or right. My mother reminded me: Look at the last two digits of these figures. I observed these figures according to the tips my mother gave me, and suddenly it dawned on me.
The original multiple of 4 is characterized by the fact that the last two digits of a number are multiples of 4, and this number is multiples of 4. Then, I found some numbers to try, such as: 437,37 divided by 4 = 9... 1. According to the law, 437 is not a multiple of 4. Then I divide 437 by 4 = 109... 1, which is consistent with this feature. I found another number, 1024, 24 divided by 4=6. I found that 1024 is a multiple of 4. I verified it again by division: 1024 divided by 4=256, so 1024 is a multiple of 4. I happily told my mother about this discovery, and my mother nodded with satisfaction.
I found this. Students might as well give it a try.
Math diary in the fourth grade of primary school: ("poetic" mathematics)
In the math interest class, Teacher Zhuang brought us an interesting topic:
During the Qianlong period of the Qing Dynasty, Emperor Qianlong traveled south of the Yangtze River and met an old man with a birthday boy.
Upon inquiry, the old birthday star 14 1 year-old, Emperor Qianlong gave the old man a couplet: flowers bloom again, plus March 7.
Emperor Qianlong asked his accompanying minister Ji Xiaolan to make a couplet, which was very difficult for him. His couplets are: Celebrate the ancient and the rare, celebrate the spring and autumn.
The teacher said, "There is a math problem hidden in this couplet. Please calculate how old this old man is? " After listening to the teacher's words, I think "Hua Jia" means 60 years old, "Re-opening" means two 60 years old, "Sanqi" means 2 1 year old, and the first part is 60× 2+21=141year old; Ancient and rare means seventy years old, and "double celebration" means two seventies. "One more year in spring and autumn" means one more year, and the bottom line is 70× 2+1=141year. It turns out that there are also mathematical problems hidden in couplets!
In fact, as early as ancient China, literati often made couplets to recite things and compare things, and they were very good at embedding some numbers in couplets, which made couplets not only literary and interesting, but also informative.
Math diary in the fourth grade of primary school: (The importance of 0)
0 is a mysterious number, as elusive as the mystery in the universe. 0 is also an important number. If you accidentally add an extra 0 or a less 0, the consequences are really unimaginable.
This math exam really made me realize the importance of 0. It was 99 points when the test paper was handed out! I made a mistake at once. The result made me dumbfounded. The result is 45000-90. "How could I make a mistake with such a simple question?" I muttered to myself. I remember that when I dictated the 45,000-90 question, I easily wrote down 50, and I was still very confident. But in the end, I got 500, which was a 0. How wrong it is! What should not be wrong is also wrong. How important 0 must be!
If I become the financial general manager of the company in the future and someone else comes to withdraw money, I would have taken 10000 yuan, but I added 0- 100000 yuan more, and I still put 10000 yuan on the bill. Then who should I ask for this 90 thousand yuan? I will bear all the consequences!
Through this incident, I understand that I should be meticulous in my work and study, otherwise the consequences will be very serious.