Mathematics is everywhere.
These days, the math teacher taught us simple division and multiplication algorithms, in order to let us work out the results of some problems faster. I thought to myself: I can calculate vertically quickly, too. Is there any other way to make calculation faster? I listened carefully to Mr. Qian's lecture with full questions, and finally understood the truth. It turns out that to simplify the operation, we must first understand the basis of multiplication and division. The basis of multiplication is: multiply three numbers, you can multiply the last two numbers first, and then multiply the first number, and the result is unchanged. The basis of division is that a number is divided by two numbers in a row, and when it is divisible every time, you can multiply the two numbers first, and then divide the numbers by their products, and the result remains the same. Let me give you an example: 25× 16=25×4×4, = 100×4, =400. How's it going? If you calculate this formula vertically, it will take about one minute, but if you use a simple algorithm to do this formula, you can quickly calculate the result. Shortly after I learned simple calculation, my father gave me a question and I answered it immediately. I calculated it this way: 35× 12=35×2×6=70×6=420. My father listened to my answer and praised me. I'll tell you a little knowledge: it's best to find a number and multiply it to get a whole ten or a whole hundred.
Simple algorithm is easy!
Comments: "Applying what you have learned" is the pursuit of the new curriculum. The young author experienced the extensive application of mathematical knowledge with his own personal experience and felt the pleasure of success.
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 4500÷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.
Comments: In a math exam, young authors can find out the causes of mistakes and make in-depth thinking and introspection, so as to realize the importance of "0" and thus lead to a serious attitude towards future work. It is really commendable to have such knowledge at an early age.
Proud "χ"
The number χ is very special. It looks like an "X".
One day, several digital friends such as "1", "2", "3" and "4" got together to compare the sizes.
Suddenly "χ" appeared in front of them and said, "Stop competing! You are no match for me! " 1 said, "How can you compare with us? You don't even know what you are, and you dare to come here and compete with us. Hey, what a young man! "
Not convinced, χ jumped in front of χ 1 and said loudly, χ- 1 = 9, χ=9+ 1, χ= 10. Look, I am older than 9! "
As soon as it heard "0" in the cave, it rolled out, pulled the number "1" and ran to "χ" and said, "χ× 1=0, χ=0, which is smaller than anyone else."
After hearing "0", "χ" is no longer proud.
(Comment: This is a very interesting math diary, which gives full play to students' imagination and knows the special number χ. )
Mathematics impressed me deeply.
Math, Math I love you, just as mice love rice. Do you know why I like math? Because of the charm of mathematics, it attracted me deeply.
I learned a new knowledge today, which is a simple addition and subtraction algorithm. After learning the simple addition and subtraction algorithm, my calculation speed is much faster and it is easier to learn to calculate. Give an example! For example: 367+498=? I just have to think like this: add up 498 to make 500, and then use 367+500. I found that I added 2 more, so I subtracted 2 from the total to get 865. And 796+295? I think so: 796 can be added to 800, 295 can be added to 300, one plus 4 and one plus 5, then the formula becomes 800+300-4-5= 109 1. Look, how convenient it is!
After learning the simple algorithm of addition, learning the simple algorithm of subtraction will be much easier. Such as: 483-299, hehe, you can find the way by gently moving your head. I'll take 299 and subtract it from 300, because it's 1, so just add 1 to the result, which is 483-300+ 1= 184, and the calculation is much simpler. However, I can warn you: it's best not to think about the minuend when doing subtraction, or you'll be in trouble!
Now, I like math more and more, because it makes me learn to calculate the results quickly, and math really makes me remember deeply!
(Comment: Learning mathematics is as hungry as "mice love rice", which fully illustrates the author's understanding of mathematics learning. )
Preview is a golden key.
After math class today, the teacher arranged for us to preview division estimation.
What is a preview? Why does the teacher want us to preview? I came home with a surprise. Check the information and ask your parents. It turns out that preview is to read the contents of the book by yourself before learning a new lesson. Mark what you don't understand, and then listen carefully in class. ) In this way, you can have a preliminary understanding of new knowledge.
I previewed the division estimation curiously. Through preview, I know that when estimating 538÷62, 538 can be regarded as 540 and 62 as 60, so 538÷62≈9. It turns out that preview can help me clear away the obstacles in math learning and have a preliminary understanding of estimation. Can quickly accept new knowledge in class. Even if there is doubt, it can be easily solved.
Therefore, it is very important to preview before class, so we must develop the good habit of preview, because successful preview can make the lecture quality higher and the learning efficiency higher, so it is the golden key to open the door to knowledge.
(Comment: Preview is just a kind of self-study behavior. The author can realize from preview before class that the formation of good habits is very important. )
A special math contest.
The annual math contest began. The forest is very lively. This year's contestants are: cotton seed, turtle, tiger and lion.
The game has already started. Teacher Swan first gave each of these candidates a test paper, and then said to them, "Whoever can calculate correctly and quickly in a certain period of time will win the Wisdom Cup Award."
As soon as Mr. Swan finished. These candidates began to write. Rabbits run fast and do fast. I saw that she was very clever and soon finished more than half of it. Come on, let's have a look at its test paper. "dizzy! ! ! "You see: 80-70= 150, 20 ÷ 4 = 80 ... What a mess! I didn't even see the operation symbols clearly.
Look at lions and tigers. Hey! Why don't you see lions and tigers? I only saw a lot of manuscripts. Before I left, I saw lions and tigers busy! It turns out that every time a lion does something, he has to take out the manuscript paper to calculate. The more manuscripts are piled up, the more lion heads are hidden. Really simple-minded, developed limbs. Tigers are more exaggerated. Every time I finish a question, I will take out my manuscript and check it. No wonder you are sweating.
Finally, let's look at the tortoise!
The tortoise is usually slow-tempered, but this time its thinking is not slow at all. See how wonderful this question is: 3456-999 = 3456-1000+1= 2457. The tortoise uses a simple algorithm to finish the test paper quickly, and it is right and fast!
Finally, the tortoise won the wisdom prize.
(Comment: You can use very humorous language to vividly reproduce the problems that students have in the process of answering questions. Four kinds of animals represent four kinds of students, some are sloppy, some are diligent and some have no brains. I hope readers can learn from it! )