Math diary, fourth grade.

After all, I believe you must have many experiences worth sharing. At this time, keeping a diary is very necessary. So do you really know how to keep a diary? The following is my fourth grade math diary, for reference only. Let's have a look.

Grade 4 math diary 1 X month x day x week x sunny.

I will drink about 5 cases of milk this semester, 5×30= 150 (yuan). Every meal is about 2~3 yuan, of which 2.5 yuan is 2.5×3×30×5= 1 125 (yuan). "What else?" I bit my pencil and said to myself, "and your school supplies." Hey, mom's home. Yes, and school supplies.

School supplies: a pencil-box 8 yuan, a pencil-box 3 yuan (very cheap, clearance goods), six pencils 3 yuan, an eraser 0.5 yuan, two triangular rulers 1 yuan, two mechanical pencil 5 yuan, 8+3+0.5+ 1+5=20.5 (yuan).

Total expenditure: 711.3+150+1125+20.5 = 20xx.8 (yuan).

Wow, I didn't expect that I, who usually don't spend much money, would ask my parents to give me 20xx.8 yuan money for a semester. It seems that I will save money!

Math diary Grade 4 2165438+1The weather is fine on Tuesday, October 27th.

I remember once, in order to consolidate my understanding of rectangular squares, my mother specially asked a question: "Put two rectangles with a length of 8 cm and a width of 6 cm into a big rectangle. What is the circumference of this big rectangle? "

I took out a piece of draft paper and drew this picture first: the calculated circumference is: 4x8 = 32 (cm) 2x6 =12 (cm) 32+12 = 44 (cm). I immediately said to my mother, "I figured it out! Equal to 44 cm. " But mother said, "There is another way." So I drew a picture on the draft. Oh, you can spell it like this, but the circumference is different, 2× 8 =16 (cm) 4× 6 = 24 (cm)16+24 = 40 (cm).

My mother seems to say to me again, "Think hard!"

Math diary, Grade 4, Monday, March 9th, sunny to cloudy.

After school in the afternoon, the class teacher gave us a homework assignment, asking everyone to find a way to measure the volume of disposable chopsticks and record the measurement process in the form of math diary. On the surface, this assignment is a mathematical practice, but in fact it may have a deeper meaning, because the use of disposable chopsticks is related to environmental protection.

As soon as I got home, I sat quietly at my desk and thought about it. Disposable chopsticks are irregular three-dimensional figures. How do we measure its volume? I reasoned, scratching my head for a while, shaking my head for a while ... finally, I got something. I can put disposable chopsticks in a container full of water, so that the water in the container will overflow. Isn't the amount of splashing water as big as chopsticks? But chopsticks are lighter than water and will float on the water. What shall we do? Can you fix chopsticks with stones or tape or something? I think it should be possible, but these methods are too troublesome to measure. If only there were a simpler way! After thinking hard, I finally smiled proudly.

Math diary, a senior, is sunny on Sunday, September 26th.

Today, my mother and I went shopping. There are so many food stores on the street! My mother and I are dazzled. My mother started to pick, and she picked left, right, up and down. Finally, she finally picked a tomato that she thought was good in a vegetable shop. Tomatoes cost 2 yuan a catty. She bought 1 kg 9 Liang, and she gave the vegetable vendor 3 yuan. The vegetable seller gave my mother 1 point. She bought ribs again. The ribs are 5 yuan a catty, and she bought 2 Jin and 2 Liang. She gave it to 50 yuan, the sparerib seller, and 39 yuan, the sparerib seller. She bought potatoes again. Potatoes are 1 yuan 1 kg. She bought 3 Jin and 3 Liang. She gave them to 5 yuan, a vegetable seller, and gave her 1 yuan and 70 cents. She bought bean sprouts again. These bean sprouts cost 65438 yuan. She bought five taels and gave them to the vegetable seller 1 yuan. The change is fifty cents. She bought ginger again. Ginger 2 yuan 1 kg. She bought 1 kg and a half, gave it to the ginger seller 10, and got 9 yuan change. She spent 18.7 yuan on dinner.

Before the fourth grade math diary 5, I always thought it was boring to learn to find the least common multiple. It was really annoying to deal with the problem of finding the least common multiple of 1 1 and 12 all day. I have always felt that it is useless to learn this knowledge in my life. However, one thing changed my view.

That was not long ago. Grandpa and I took the No.2 bus to the Youth Palace. Just as the bus was about to leave, 1 the bus just started at the same time as us. At this time, grandpa looked at the two cars in front of him and suddenly smiled and said to me, "Zequn, grandpa has a question to test you, okay?" I answered confidently: "OK!" "Then listen carefully. If the 1 bus runs every 3 minutes and the No.2 bus runs every 5 minutes, how many minutes does it take for the two cars to leave at the same time? " I paused and said, "Grandpa, your question still needs one condition: the starting point of bus 1 and the starting point of bus 2 are in the same place."

Math diary, Grade 4 18 The weather is fine on Monday, June 4th.

Today, I went to the second class of "Independent Practice" and did the last topic "Practice Development". The topic is like this: Xiao Mahu regards 13 of a topic as 3 1, and the calculated answer is 450 more than the original number. I thought for a while, but I couldn't figure it out. After a while, I finally figured it out. I first worked out 31-13 =18,450×18 = 8100, and then I worked out 8 100-450 =. The next day, Independent Practice was published. I made a mistake on the last question. After the teacher's answer, it turned out to be like this: 31-13 =18,450 ÷18 = 25,25×13 = 325. I must carefully examine the questions in the future, or I will make mistakes again.

Math diary, Grade 4, Grade 7 Today, I waited patiently for my father to buy wine at the gate of the community. Suddenly, the security guard spoke and said, "Little friend, it's Arbor Day soon. We may plant trees in Haiqinyuan Community. May I ask you a question? " I was shocked at that time, and the security guard wanted to ask me questions! Uncle Security then asked me, "We want to plant 18 trees, both sides. How many trees should we plant on each side? " I quickly replied: "9 trees." Hearing this, the security guard happily said to me, "Little friend, you are so smart!" " "

After a while, my father came back and the security guard gave me a big compliment in front of my father. I was flattered to hear that.

Oh, so this is the division taught by Teacher Zhang! I can also do formulas.

18÷2=9 (tree)

Grade 4 math diary 8 Today is the second day of the first month, which is a good day for my mother and I to go to my grandmother's house.

In the morning, I got up early and went shopping with my mother to buy three pieces of meat. A piece of meat is 2.5 Jin, and a Jin of meat 16 yuan. My mother handed in 120 yuan. Mom also bought 3 boxes of apples and spent 150 yuan. Going to the wholesale and retail store, my mother bought three more "Want Want Gift Packages" and handed them to 150 yuan. Then we went back to grandma's house happily.

When I arrived at my grandmother's house, my grandmother, uncle, aunt, cousins were all very happy.

After dinner, when we were going home, my uncle, aunt and grandmother all gave me red envelopes. When I got home and opened the red envelope, I was very happy to get eight yuan 100 yuan.

A meaningful day passed quickly!

One day in math diary, Grade Four, the symbol girl was noisy in the symbol kingdom.

Book: I'll give you 1 questions. Take your positions. The topic is this:

3 3 3 3=6

The symbols are all standing, there is nothing wrong!

(): It's a good thing it's not as ugly as the slogan, otherwise we'll become ugly ducklings when our neat queue is in a mess.

Hearing (), the ship bowed its head.

● Are my two black balls so annoying?

Book:+How can you say that? We are all good friends and must help each other!

The symbols were ashamed and let Yan join them again. Children, do you know how they are combined?

Grade 4 math diary 10 20xx year x month x day week x sunny.

My sister and I are having a good time, and my grandmother insists on calling me and asking me to settle her account.

Grandma bought 3 Jin 4 Liang eggs, 3 yuan and 50 cents per Jin. Grandma handed it in 12 yuan. How much should I get back? As soon as grandma's voice fell, grandpa said, "Change 1 minute!" I don't believe that grandpa can calculate so fast, so I use the mathematical knowledge I have learned to calculate: unit price multiplied by quantity = total price; Spent money = recovered money, exactly the same as grandpa's, and the change is 1 minute. I asked grandpa why he calculated so fast. Grandpa originally divided 3 yuan's 5 angles into 3 yuan +5 angles, and counted 3 first. 4 times 3= 10. 2 yuan, count to three. 4 times 0. Five is three. Half of 4 is 17 yuan, so a * * cost 1 1. 9 yuan, paid 12 yuan, of course, a dime. After grandpa finished, I realized that he used multiplication and division.

Through this incident, I understand that mathematics can be used anywhere around us. Let mathematics serve us!

Math diary, fourth grade, 1 1 math activity month of grade three, the competition is at 24 o'clock in our grade. At that time, I often played with my mother until 24 o'clock.

Once, our cards were 7, 8, 4, 8. It suddenly occurred to me that if there are four, there must be six, that is, 8/8= 1, 7-1= 6,4 * 6 = 24. My mother smiled and said to me, "There is another way." I thought about it, and suddenly I had an idea: 7*8=56, 4*8=32, 56-32=24. Mom asked again, "What about 4, 10, 10, 1?" I think, if there is 4, there must be 6, but what if 6 can't be found? Mom said: Don't go into a dead end. It suddenly dawned on me that multiplication was replaced by addition: 4* 1=4, 10+4+ 10=24.

My mother smiled and said that I know everything, I am smart, and I am very happy.

Counting 24 o'clock often can improve my calculation ability. Let's have a try!

Saving method of toilet bowl

Math diary, Grade 4 12, came across such incredible data in a book today: "A piece of paper with a thickness of 0.0 1 cm is even thicker than Mount Everest after being folded in half for 30 times?"

This data is a bit "absurd" no matter how you listen to it. 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.

Comments: Reading, thinking, questioning and verifying, you have good study habits and correct learning methods. With these, you will succeed.

Math diary, Grade Four 13 In the math interest class, Miss Wang 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, Lao Shouxing 14 1 year old, Emperor Qianlong gave the old man a couplet: bloom reopened, plus March 7th.

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, scholars often made couplets to recite things and metaphors, and they were very good at embedding some numbers in couplets, which made them not only literary and interesting, but also informative.

Math diary, Grade Four14 sunny day in 20xx years.

It was a rainy Tuesday in Mao Mao. I went to school with an umbrella and suddenly found the study garden on the first floor surrounded by many classmates. Curiosity immediately drove me to run to see what had happened. I took a closer look, and with a "wow", there was a new topic in the wide angle of mathematics! No wonder it attracts so many students to see it! I got into the crowd and saw this question written on it:

A person wants to cross the river by boat. He only has a boat and three things: a chicken, a dog and a basket of vegetables. You can only take one thing across the river at a time. When people are not around, dogs eat chickens and chickens eat vegetables. How can I ensure that the three things I bring are intact?

After reading the topic, I thought about it. ...

I had a brainwave, and the answer was that dogs can't eat vegetables. They can send the chickens first and then send them back empty-handed. Considering that chickens can eat vegetables, bring them back, take the dogs and vegetables together instead, and bring them back at last. Yes, this is the answer. I smiled sweetly.

It's nice to have a wide angle in mathematics. I will definitely come here often in the future.

Grade 4 math diary 15 March 10 Wednesday sunny.

Last week, we studied fractions. Fractions have numerator, denominator and fractional line, for example, 1/3, where 3 is denominator, 1 is numerator and the middle horizontal line is fractional line.

Scores are used in many places in life. For example, a book has thirty pages, and each page is 1/30 of a book. Fractions can also be used to add and subtract! For example, half plus half equals two, which is 1. Why is this happening? If you divide a cake into two parts, each part is 1/2 of the cake, and then put the two parts together, there are two parts 1/2, which is just a cake. When adding and subtracting fractions, if the denominator is the same, only the numerator is added, regardless of the denominator. And 2/2 of the numerator and denominator are the same, which is 1.

I also learned to compare the size of fractions. The teacher taught us the formula: numerator is the same as denominator, the fraction with large denominator is small, and the fraction with small denominator is large; Denominators are the same as numerators, with large numerator scores larger and small numerator scores smaller.

The teacher also reminded us that when writing scores, we usually write scores first, which means average score, then denominator and finally numerator.