Third grade math diary

25 articles for third grade mathematics diary Time flies so fast, and the day is coming to an end. I believe you must be deeply touched. It is time to calm down and write a diary. But how can you write a good diary? The following is a third-grade mathematics diary that the editor has collected for everyone. It is for reference only. Let’s take a look.

Third Grade Mathematics Diary Part 1 Today, my mother and I went to the bookstore to buy books. I found a question in a book called "Fun Mathematics" that puzzled me. This question is like this: Bill bought a dog for 10 yuan and sold it for 15 yuan, then bought it back for 20 yuan, and finally sold it for 25 yuan. Did Bill make money or lose money in the end? I think buying it Buying and selling, selling and buying again, and over and over again, my thinking became confused. I asked my mother, and she said: "If you can classify according to the quantity of "buying" and "selling", it will suddenly become clear. I think: the money used for "buying": 120=30 (yuan) . The money earned from "selling": 15+25=40 (yuan). Obviously, Bill made money, 40-30=10 (yuan)! What a wealth of mathematical knowledge!

Third Grade Mathematics Diary Part 2 Today, my mother took me to the market to buy vegetables. I found that there was a rectangular electrical appliance on every stall. It was marked on the front: kilograms. I asked my mother curiously, what did she say? The grams and kilograms I just saw are used to weigh things and represent weight units. When I got home, I looked for a lot of things in the house: a box of tea (125 grams), a lipstick (gram), a box of urea cream (48 grams), and then my mother told me. : Solids that can be picked up by hand are expressed in grams, and liquids that cannot be picked up by hand are expressed in L. It turns out that I don’t know so much knowledge in life.

Third grade mathematics diary. 3 Today, I learned what perpendicularity is. It turns out that two straight lines that intersect at right angles are perpendicular to each other. One of the straight lines is the perpendicular line of the other straight line. Their intersection is called the vertical line. In addition, I can also draw perpendicular lines and parallel lines. Draw a perpendicular line from a point outside the straight line to the straight line, and the length of the line segment from this point to the vertical foot is the distance from the point to the straight line. After these two lessons, I gained a lot of knowledge.

Third Grade Mathematics Diary 4 There is a height measuring ruler on the wall of our house. I use it to measure my height every year. Last year my height was 1m10cm. This year my height was 1m16cm, 116-110=6 (cm). I I have grown 6cm this year. I asked my mother: "When will I be as tall as Yao Ming?" My mother said: "As long as you eat more every day, are not picky about food, and keep exercising, you will grow into a little giant like Yao Ming in the future." .

Third Grade Mathematics Diary 5 One weekend, a good friend from my yard came to my house to play. I was going to tease her, so I said, "Let's play a game." Each of us can only shout out the numbers 1, 2, 3, 4, and 4. Whoever shouts 32 first wins, and I will count. If you lose, you will be punished. I will shout first, 2. She thought for a while and said, "No." You already know the rules, I will lose no matter what. "Because 32-2=30, 30=5×6, 5=1+4=2+3, so I can win as long as I am the first to shout 2 and the sum of the number she shouted is 5. Originally, I I wanted to take advantage of this rule, but I didn't expect that she would see through it. It seems that I need to strengthen my math knowledge.

My mother asked me to buy 4 heads of lettuce and two lettuces today. When I arrived at the vegetable store, I chose four heads of lettuce and asked the grandma to bring me two yuan of tofu. Then she told me how much the lettuce and tofu cost. **It's yuan, she should ask me for yuan. After I paid, my parents praised me for the delicious food.

Third grade mathematics diary. 7 On August 1, my parents, grandma, uncle and I went to Penglai Changdao for a trip. We took the bus at New Century at 9:00 the next day and walked about 10 kilometers. hours. We took a boat ride for about 40 minutes to reach Changdao. We stayed in the fisherman’s courtyard and ate seafood every day, including shell meat, fish dumplings and fried yellow croaker. In the morning, we took a boat to go fishing. The adult ticket was 40 per person. Yuan, the ticket for children is 40 Yuan for those who are taller than 1 meter, and 20 Yuan for those who are not taller than me. So for our family of three, the ticket is 240 Yuan. I caught a sea shell and a starfish. In the evening we went to the beach night market. My mother bought me a jade necklace and three puppies made of shells. She also bought three jade necklaces for my brother and sister. *It cost 50 yuan.

Third Grade Mathematics Diary 8 Today we went shopping. We bought 2 pounds of cucumbers, 1 pound of tomatoes, and 2 pounds of my favorite potatoes. On the way, my father asked me: "There are exactly 4 cucumbers. We are a family of three. My mother does not eat cucumbers. How many cucumbers can each of us eat? I remembered the division method I learned before, and I said: "4divide; 2=2, each person Eat two." Dad nodded and said with a smile: "You are so right! I am very happy today. Not only did I follow my father to buy vegetables, but I also know how to count. It's great.

Third Grade Mathematics Diary Chapter 9 Tonight, I just finished my homework and had nothing to do, so I said to my mother: Mom, I have finished my homework, what should I do now? Mom said: Now, you Just help me buy 3 pounds of apples! I agreed. My mother gave me 10 yuan and said: buy half a catty more! I agreed and happily took the money to the fruit shop, picked out three and a half catties of fruit, and said to the salesperson: help me do the math. . Auntie said: You can do the math first. I thought about it and asked my aunt: Is it 3 × 3 = 9 (yuan), then 3 yuan ÷ 2 = 1 yuan and 50 cents, and finally 9 yuan + 1 yuan and 50 cents = 10 yuan and 50 cents. I said again: No, Auntie, I don’t have enough money, I’m still 5 cents short, what should I do? I thought about it and said: Then just add my pocket money! I took my pocket money, Got in. Say to aunt: That's enough now. The aunt said: You are so smart, you used your wisdom to buy the apple!

Third Grade Mathematics Diary 10 These days I have been thinking about another way to find the volume of a cylinder. With my It feels like I listed such a formula: diameter × diameter × height × ÷4. When I got home from school, I started to prove whether this formula was correct. I tried it. Using the solution in the textbook and my solution to calculate the volume of a cylinder were exactly the same. I tried it many times and the result was the same. I was very puzzled as to what my solution meant. After some thinking and proof, I found that the cylinder was regarded as a cube with equal diameter and height. Then find the volume of the cube, and then according to the ratio of the cylinder to the cube: 4, it becomes the volume of a cylinder.

Third Grade Mathematics Diary Chapter 11 Today, grandma bought a duck weighing two kilograms, which cost 15 yuan per kilogram. She also bought two potatoes and half a pound of pork. Green vegetables cost two yuan per catty. Grandma bought one and a half catties for 3 yuan. In the evening, grandma made shredded potatoes, fried vegetables, and braised duck. Divide the shredded potatoes into 5 portions. My mother and I ate two-fifths in one sitting, and my grandma, aunt, and sister ate three-fifths. Grandma also made soup and divided the soup into six parts. We drank four-sixths of the soup in one go, and this fraction can be divided into approximately two-thirds. This fraction is also the simplest fraction. My mother told me to eat more soup dregs, because 15% of the nutrition is in the soup and 85% is in the soup dregs. Today, I not only understand mathematics, but also know how to mix nutritional medicine.

Third Grade Mathematics Diary Chapter 12 In the math class a few days ago, the teacher gave us a word problem. This question said that the largest bird egg in the world is an ostrich egg, and its egg weighs 1,300 grams. How much does the smallest egg weigh? I had a question mark in my mind. After surfing the Internet and reading books in various ways, I finally found the answer in the "Chinese Youth Encyclopedia": the smallest egg is a hummingbird egg. A hummingbird mother lays 2 to 1 eggs at a time. They are only about the size of a bean and each egg weighs a gram. About 200 hummingbird eggs are as big as one chicken egg. After a baby hummingbird lives for about 20 days, it can fly out of the nest to look for food and start living independently in the wild. What interesting knowledge, it can not only learn, but also increase extracurricular knowledge, it is really the best of both worlds.

Third Grade Mathematics Diary Chapter 13 In the evening, my brother said he was hungry and wanted to drink milk powder. I saw my mother washing clothes, so I helped to make milk powder for my brother. But I didn't know how much water and how much milk powder I needed, so I ran to ask my mother. My mother told me that I need 180 ml of warm water. I asked my mother how many spoons of milk powder I needed. My mother said: "30 ml of warm water requires 1 spoon of milk powder. How many spoons of 180 ml of warm water do you need? Do the math!" I added it with my mouth and counted a few 30's with my fingers. :330=60, 630=90, 930=120, 1230=150, 1530=180. Finally, when I counted the sixth 30, it added up to 180. I quickly told my mother that it was 6 spoons. Mom smiled and said: "That's right, but if you learn multiplication and division, it will be easier to calculate 180÷30=6, and you can calculate it quickly." It turns out that it can be so simple! Mathematics is all around us. , I want to study it hard!

Third Grade Mathematics Diary Chapter 14 The weather was sunny this morning, and my sister Xiaer and I went to Hangzhou Paradise to play. We went to ride the Ferris wheel. The Ferris wheel has small compartments in four colors: red, yellow, blue and green. There are 4 compartments of each color, and each compartment can accommodate 4 people. My mother asked me: "How many people can sit in all the yellow compartments? How many people can sit in the entire Ferris wheel?" I quickly replied: "The yellow one can seat 16 people, because the yellow one has four small compartments, and each one can sit There are 4 people, so it is 4+4+4+4=16 (people). The Ferris wheel has 4 colors, and there are the same number of each color, so it is 16+16+16+16=64 ( people). The Ferris wheel can seat 64 people in total." After answering the questions, we got on the Ferris wheel together. Dad also ordered delicious food for us, which was really delicious and fun. After we got off the Ferris wheel, my father told us: "When we learn multiplication in the future, this will be easier." I am so looking forward to learning multiplication!

Third Grade Mathematics Diary 15 Sixth Day of the New Year , my father and mother took me to Taicang?m Shanyuan Baiyuan. I first went to the ticket booth and bought a ticket for the "Luxury Flying Chair", which cost 10 yuan. There are many swing-style seats around a large column.

When it starts to rotate, the outer layer of the large cylinder slowly rises, and the seat continues to rise while rotating, and people fly up on the seat. Flying faster and faster, some people began to scream. But I don't feel scared at all. Then we bought three more tickets for the "Flower Basket Observation Car", each priced at 20 yuan, totaling 60 yuan. Finally, my mother and I went to take the "Space Walk" ride. Each ticket was 15 yuan, totaling 30 yuan. In this case, we spent a total of 1630=100 (yuan). While playing, I met a classmate. He had a 40 yuan package in his hand, and I heard that he could play eight events in total. Then I suddenly realized that if we bought a 40 yuan package from the beginning, it would cost 100 yuan to play these three projects without a package, but with a package we only need to use 40 yuan, which is a full 60 yuan cheaper. Alas, I really lost money! So I want to tell the children, if you want to save some money next time you go here to play, you should buy a package ticket. This is my advice!

Third Grade Mathematics Diary Chapter 16 Today, our family went to the supermarket to buy things. We first went to the kitchen supplies counter and bought 2 tubes of fresh-keeping bags for 1*** yuan. My mother asked me how much 1 tube cost? I couldn't help but said: "1 tube is ￥ "Then we went to the daily necessities counter, and we bought three large shoe polishes for 15 yuan each. Dad asked me how much each cost. I said: "15 yuan divided by 3 equals 5 yuan." Then we went on. We came to the facial tissue counter again, and we bought 3 packs of facial tissues for 18 yuan. My brother asked me: "How much is 1 pack of facial tissues?" I confidently said: "It's 6 yuan." Then we went to the Apple counter and bought 3 packs of facial tissues. A pound of apples cost 4 yuan per pound. My uncle asked me: "How much is a pound?" I said without hesitation: "It's 12 yuan." We finally went to the dental appliance counter and bought 2 Yunnan Baiyao. Toothpaste costs 28 yuan a tube. The eldest mother asked me: "How much does 2 tubes cost?" I hesitated for a while and said: "It's 56 yuan." It turns out that there is math involved in buying things!

Third Grade Mathematics Diary Chapter 17 In today’s fun math class, Teacher Xu taught us to use plasticine and toothpicks to make three-dimensional figures. Teacher Xu asked us to first build a triangle and a cube according to the three-dimensional figures on the big screen, and then use the method taught by Teacher Xu to create an interesting three-dimensional figure ourselves. The children used their rich imagination and came up with a variety of three-dimensional shapes. Some built the rectangular parallelepiped that they will be doing in the next class, some built the same shape as a house, and some built a very complicated iron tower. Especially classmate Li Yuxin, she built a three-story house, which was very difficult and was not completed until the end of get out of class. Her work was praised by the whole class. In this fun math class, students learned that even with the simplest materials, they can create complex shapes and make the shapes ever-changing. Today’s math class was so fun, and the students all had smiles on their faces! I hope there will be more and more classes like this in the future, making our math learning more and more enjoyable!

Third Grade Mathematics Diary 18 During the summer vacation, I learned the modern intellectual jigsaw puzzle. There are 5 pairs of jigsaw puzzles, each consisting of 7 pieces. My mother asked me how much a piece of cake like this cost? I calculated it like this, adding 7+7+7+7+7=35 one by one in the notebook. My mother told me that I can calculate it quickly using the multiplication formula I just learned! I had an idea and silently thought about the multiplication formula related to 7. "Five seven thirty-five" is the same as the answer I got by adding. Wow! It turns out that the multiplication table is so convenient. Mom gave me a thumbs up. The jigsaw puzzle can be played with a single pair or with multiple pairs. It can be used to build people, fish, words, rockets, ships, animals, etc. As long as you use your brain, you can create various shapes. Today I worked one pair at a time, and in total I did nine pairs. My favorite one is the picture of mother and daughter having fun together. Look! I used long right-angled boards and large boards to spell out my mother’s body, just like I was being held in my arms and laughing together. The Modern Intellectual Tangram is so interesting, let’s play together, classmates!

Third Grade Mathematics Diary Part 19 Today I went to read a book with my good friend Zhou Ziran. We came to the reading room. There were so many books in the reading room! There were picture books and story books. We first came to the picture book area that we liked most. Zhou Ziran and I counted together and found that there were 20 books in each row. At this time, Zhou Ziran wanted to test me and said to me: "Do you know how many books there are in the picture book section?" I looked up and counted and found that there were three rows in the first row, and each row contained 20 books. Then there are 2220=60 (books) in picture book area 1***. Zhou Ziran agreed very much after hearing my answer. So, we read together in the reading room from one o'clock in the afternoon to two thirty. I read 30 pages of the picture book and 28 pages of the story book. I read 328=58 (pages) in one go. It took me an hour and a half in total. One hour is equal to 60 minutes, half an hour is equal to 30 minutes, that is, I watched 630=90 (minutes). Reading time flies so fast! Today is such a happy day!

Third Grade Mathematics Diary Part 20 Today, I played dominoes at home. There are 4 colors of dominoes: light green, dark green, orange, and yellow. I counted, there were 20 dominoes of each color. I used multiplication to calculate, and the total number is 4×20=80 (pieces). I loaded the dominoes into the domino train and counted them. I could fit up to 27 at a time.

Each train will automatically line up the dominoes in a straight line. I thought: How many times does the small train have to run to finish transporting it? So I calculated it by addition, 27+27+26=80 (pieces), the small train needs to run 3 times to complete the transportation, and the last small train is longer than the previous one. One domino was missing in the 2nd trip. I knocked down 3 rows of dominoes at the same time and found that the group with 26 dominoes won. I wanted 3 groups to win at the same time, so I removed 2, so the total became 26+26+26=78 (pieces). Then, I knocked down 3 rows at the same time, and this time 3 groups won at the same time. Dominoes are so fun, I will try new tricks next time!

Third Grade Mathematics Diary Chapter 21 Happy Saturday is here, and I accompany my dad to work in the store. Just after arriving at the store, my father received a call from a customer. It turned out that I wanted to buy the portion tray on the warming table. After answering the phone, my father said to me: "Dad, let's test you today! The customer wants to buy 4 portion basins on the warming table. There are 6 portioning trays on the warming table. How many do you need?" I said I thought in my mind that 6+6+6+6=24 (pieces). Dad asked again: "Do you have any other algorithms that are more convenient and faster?" I then thought about the multiplication formula I just learned during the summer vacation, "four six twenty four", I quickly calculated it, and the answer to addition is the same. After hearing the answer, my father gave me a thumbs up. Dad said: "The number of pots in our warehouse is 12 per box, so how many boxes do we need to send them?" I quickly thought about it in my heart, 24-12-12=0 is exactly 2 boxes. I quickly told my dad, "Just 2 boxes." Dad smiled happily and treated me to ice cream. It turns out that mathematics is everywhere in our lives.

Third Grade Mathematics Diary Chapter 22 Tonight, after finishing my homework, my mother asked me to review the multiplication and division formulas. Thinking of the formula, I sighed, sat down at my desk reluctantly, and began to answer the questions one by one, then four by two. At this time, my father heard my weak voice and walked over. He looked at me seriously and suddenly smiled. He told me that mathematics is a science, a profound and interesting knowledge. Many inventions and creations in our lives are inseparable from mathematics. At this time, my father looked at the multiplication table and told me a very interesting multiplication formula with his fingers. He asked me to hold out ten fingers, and then one in turn. In this process, the closed hand index represents another factor besides 9, minus 1, and you get tens digits; the unclosed hand index is single digits. For example, four fingers are closed and six fingers are not closed; then, it is 4 times; 9=36, of which 3 is derived from 4-1. During the test, remember, 4+6=10, which is ten fingers, haha! Mathematics is really interesting!

Third Grade Mathematics Diary 23 Life is full of mathematics, and mathematics is generally applied to In life, one afternoon, I encountered a mathematical problem in life. That day, my mother gave me a math problem and asked me to measure the volume of a chopstick and record it in a diary. I sat on the sofa and looked at the chopsticks carefully. This chopstick is an irregular three-dimensional figure. How to calculate whether it is thick or thin? Suddenly, an idea came into my mind. Place the chopsticks in a container filled with water. Isn't the volume of the water that comes out the same as the volume of the chopsticks? However, the chopsticks are too light and will float on the water. So, I decided to wrap the chopsticks with tape and put them into the water. The overflowing water minus the weight of the tape is the volume of the chopsticks. I followed this method and found out that one chopstick weighs grams. Through this experiment, I realized that the method is important, but not necessarily this method can be successful. Sometimes it is necessary to adapt the method to be successful.

Third Grade Mathematics Diary Chapter 24 In the morning of the day, the sun was shining brightly and there was no cloud in the sky. I was walking on the street after buying breakfast, and suddenly I saw many people gathered around a table. I ran over and took a look. It turned out to be a lottery. I felt very bored when I saw it. , I wanted to walk away in a hurry, but then I heard someone say that the grand prize was 50 yuan, and I immediately became interested. Quickly ask the shopkeeper what the rules of the game are. The shopkeeper said: "There are 24 cards here. 12 cards are 5 and 12 cards are 10. If you draw 12 cards at a time, if the total is 60, you can get a 50 yuan prize." I quickly took out 5 yuan and started I drew cards, but I didn’t win the prize 12 times. When I got home, I thought about it carefully. The total number is 60. Then all 12 cards must be 5. The best case is that it is 5 every time. It will cost at least 6 yuan to catch 12 5s for the 12th time, but it will cost at least 6 yuan. If the number of the cards drawn is 10 or the sum is the same, then it means how much it costs to draw it as many times as possible. I understood the mystery and hurried to the original store, but the store manager had disappeared and I could never find him again.