Math diary's 400-word encyclopedia
One day, I was doing my math homework in the classroom. Then, I met a math problem that I couldn't understand. This math problem is: Find the volume of a cuboid. This question gives me two conditions. The cross-sectional area is 30 square centimeters and the width is 6 centimeters. I think: isn't the volume of a cuboid multiplied by its width and height? Why did the topic only give us the area and width of the bottom? I haven't thought about it for a long time and I don't know how to do it. So I went to ask the math teacher.
The teacher looked at the topic and told me that the cross section is the bottom area of the cuboid, and the width on the topic indicates the height of the cuboid. Now I finally understand how to find the volume of a cuboid. I learned a new knowledge. I'm so happy.
Later, when I saw such a topic, I was no longer afraid. I used the method taught by my teacher to distinguish the calculation method of cuboid volume from this kind of problem. This knowledge is really helpful to me. I use it to solve many problems that I can't understand. My heart is happier than anyone else, because I understand a truth: mathematics is full of mysteries, waiting for us to explore, make good use of it and solve greater problems and tests. The knowledge of mathematics is really endless, and we can't finish learning it. I hope to try my best to learn profound math problems.
Math diary's 400-word encyclopedia II
Today, I followed my mother to the market to buy food. Mom said, "I will test you today. Will you buy a dish you like?" My mother gave me 20 yuan to watch my performance. "Make sure the task is completed." I said confidently. So, I walked and watched, and came to the vegetable area. At this moment, I saw an aunt selling white and tender fresh mushrooms. I think: the leftovers at home can be cooked with mushrooms. So, I asked the aunt who sells vegetables: "Aunt, how much is a catty of mushrooms?" Aunt smiled and said to me, "Little friend, this mushroom costs 7 yuan a catty. How much catty do you want?" "Aunt, I only need to buy half a catty." I think: 7 divided by 2 equals 3.5 yuan, 20 minus 3.5 equals 16.5 yuan. After thinking about it, I gave my aunt a note of money from 20 yuan, reminding her that she still needs to find me 16.5 yuan. I went to the meat department again and saw an uncle selling meat, so I asked, "Uncle, how much is a catty of meat?" "10 yuan a catty." "Then I'll buy a catty." I thought: 16.5 minus 10 equals 6.5 yuan. I handed the 10 yuan in 6.5 yuan to my uncle.
When I came out of the food market, my mother smiled and said to me, "Learn to buy food!" " When she saw that I had both meat and vegetables and 6.5 yuan in my hand.
Through this test, I feel that there are many mysteries of mathematics hidden in our lives, and the ability to learn mathematics is really important. And don't be proud. You should study hard and master more math skills in order to apply what you have learned and solve the problems around you.
Math diary's 400-word encyclopedia, article 3.
Today, I came across such incredible data in a book: "A piece of paper with a thickness of 0.0 1 cm is thicker than Mount Everest after being folded in half for 30 times?"
No matter how you listen to this data, you feel a bit "wild". After all, it is a thin piece of paper. Can folding in half really surpass Everest? But many unexpected things may happen, so only through calculation can we uncover the mystery of all this.
Immediately I multiplied 0.0 1 cm by 2,1* * 30 times to get10737418.24cm.. Then, I converted the height of Mount Everest from 8848. 13 m to 8848 13 cm. By comparison, it is obvious that the thickness of paper folded in half for 30 times is indeed better than the height of Mount Everest, which is more than 10 times of the latter.
In fact, amazing data like this are everywhere in ordinary life, as long as you have a pair of eyes that are good at discovering.
After reading math diary's 400-word encyclopedia, I will read:
1. math diary 400 words
2. math diary's four 400-word compositions in the fourth grade of primary school.
3. Three selected compositions of 400 words by math diary in the fourth grade of primary school.
4. Grade five math diary 400 words.