Math diary

How time flies! One day has passed. There must be many feelings. Act now and keep a diary. Is it impossible to write without a clue? The following is an article on math diary compiled by me for your reference, hoping to help friends in need.

Math diary 1 20xx April 1 Saturday Weather: sunny.

A "I don't know how" class came. That class was attended by teacher Liu. Before that, our respected teacher Liu prepared some courseware for us. Teacher Liu played the courseware for us, which was rich in content! There are: examples, answers, concepts ... Although the courseware background is "dull", it is very exciting. The content of the video lesson is about the surface area of cuboids and cubes, which we "probably" learned, so this video lesson is to make us more solid and deepen our understanding. After this lesson, we have a better understanding of solving the surface areas of cuboids and cubes. Each cuboid has 12 sides, 8 vertices and 6 faces.

We have learned to find the area of a rectangle. But because every two opposite faces of a cuboid are the same, we can first find out the three faces of the cuboid, and then multiply them by 2, and the result is the total area of the six faces of the cuboid. The cube is the same, because its six faces are the same, so we only need to find one face of the cube and multiply it by 6 instead of 2. As long as you know the truth, you won't learn by rote. Teacher Liu asked us to make a cube and a cuboid, so that we could compare them. Teacher Liu really thinks of us! There will be many tests waiting for us in the future. Be sure to understand and think, and memorize only when you have to, because rote memorization will not only be confused with other knowledge, but will soon be forgotten.

Math diary 2 Today, I read from a story book that an ancient celebrity was frugal and helped his father share the burden. I was deeply moved, so an idea came to my mind: calculate my expenses for one semester.

First of all, I investigated my parents and got to know the actual situation. Then, I started spending statistics: tuition 278 yuan, books 106 yuan, interest classes 105 yuan, meals in 500 yuan, accommodation in 500 yuan, milk 135 yuan, a *** 1624 yuan. Wow, that's amazing!

But these expenses are only on campus, not outside. English interest class needs 500 yuan, art interest class needs 500 yuan, stationery needs about 1 10 yuan, and bread and cake after class needs about 160 yuan, totaling 2894 yuan. Wow! This money is enough to buy a 34-inch color TV!

Through this statistics, I understand that in fact, the expenditure of a semester is very large. In order to reduce the burden on mom and dad, we must save money, learn to be thrifty, don't waste money, and be a diligent and thrifty boy.

This kind of homework provides students with flexible space for self-construction of knowledge, enhances students' participation in learning, and stimulates students' creativity and self-evaluation. Teachers can also evaluate students' mathematics emotion and learning attitude from this aspect.

Math diary 3 It was a sunny day, and all the students were full of energy and returned to school happily. The classroom is particularly quiet. Because the headmaster will give us a math lesson in person.

The headmaster came and all the students greeted him kindly. "class." "Stand up", "Hello, teacher." "Please sit down." In this series of procedures, the class began. When the headmaster gave a lecture, we listened very carefully. Maybe you will ask, "Your topic is an unforgettable math class, but when you hear this, you don't think it is unforgettable." Don't worry, just listen slowly. Because we are the famous "first" in our school, the headmaster asked us, are we all people with two eyes? We answered "no" with one voice. By the way, animals also have two eyes. Did the headmaster just ask us a common-sense question that everyone knows? No, he is also telling us that although your Class 5 (2) is "far away" from our school, compared with other schools, we are "far away". Therefore, you should not be arrogant just because you won the first place in your own school, but should work harder and strive for better results.

It is precisely because of the headmaster's short 45-minute class that we understand the truth from the things around us. "Students, congratulations on your success in winning the first place in the school and continuing to win glory for the school." Suddenly the whole class cheered and applauded. "Bell." The bell rang, ending our lively and interesting math class.

Unforgettable 20xx Math class on March 2nd.

Tuesday, April 6, math diary 15

I woke up at eight o'clock today, and my parents had finished breakfast. I decided to make a nutritious breakfast-black sesame soybean milk. Take out the soymilk machine first, then put the washed 1 cup of dried soybeans and 1/5 cups of black sesame into the soymilk machine, add a proper amount of water, and start. After more than 20 minutes of "bang" sound, black sesame soybean milk is finally ready. I drank 1/5, and the remaining three people in my family shared it equally.

After breakfast, my father took me shopping in RT Mart, Pinghu! Before leaving, my mother asked us to buy a bag of black fungus, so we started to buy it on the exquisite shelves. Dad always thought that "expensive is good" and insisted on buying that expensive bag of black fungus. But which set meal is more expensive? It depends on the unit price. Look at this bag first, 15 yuan 150g, 15÷ 150=0. 1 yuan/gram, and then look at the package, 12 yuan 100g, 12÷ 100=0. 12 yuan/gram. 0。 1 yuan -0. 12 yuan. Oh, it turns out that the second set meal is expensive, so I'll take the second set meal ... We spent 136 on this shopping. 8 yuan. It was 1 1: 30 when I got home. I feel a little tired, but I am very happy, because I have learned to solve problems in life with mathematical knowledge!

Math diary 5 Not long ago, we learned axisymmetric graphics. I think it's amazing! I found a secret in an exam. For example, in this picture, at first I only saw one axis of symmetry. I accidentally put the test paper on the ground at that time. I bent down to pick it up, but I accidentally saw another axis of symmetry. I am overjoyed! I tried to look at this figure from different angles and found three axes of symmetry! I know, a figure, as long as you change an angle, will have new discoveries, just like this figure, and finally found several symmetry axes. This is really a good idea! This is the same as the story of painting carambola.

Don't let the "checking calculation" slip away

Many large and small math exams are always finished by candidates, and most people don't check or check; The results of an exam came out, and about 50% people didn't do well in the exam because of carelessness. So, what kind of checking calculation is correct?

According to my experience, the check calculation of oral arithmetic problems is to add/subtract/multiply/divide one of the numbers to see if this number is another; Fill in the blanks are generally formulas and concepts. Just read and recite, and the correct answer will come out. Look up the equation and substitute the number into the original formula to see if the left and right are equal; The most difficult and troublesome thing is the application problem. First of all, we must ensure that the formula conforms to the meaning of the problem. If you are not sure, you can write down the calculation on the draft paper first, and then check it by reverse calculation.

Well, my friends, checking is a strange thing. If you work hard, it will give you unexpected surprises. If you are lazy, it will make you uncomfortable. Friend, don't let the check slip away, because it is lonely and you will be lonely.

Finally, I wish you a good check and good results.

Math diary 6 Our children say that Chinese New Year is the time to receive red envelopes, and this year is no exception. On New Year's Day, I visited my relatives' homes, like my grandparents' brothers and sisters, who are all seventy or eighty years old or even ninety years old. They kept the traditional customs. As long as I send them a sincere blessing, they will give me a big red envelope. At the end of the day, I received sixteen red envelopes.

I began to check the money inside. My father and boss gave me 1600, and my parents gave me two red envelopes, 200 for my mother and 800 for my father. My aunt, uncle, grandmother and grandfather each gave me 100 yuan, and my grandparents each gave me 500 yuan, which added up to 1000 yuan. My grandparents' relatives and friends gave me five, one in 200 yuan, and one from my neighbor.

Among the 5,200 yuan, the person who gave me the most money was my father's boss, accounting for about 30.8% of the total money, followed by my father, accounting for about 15.8%, and grandparents, accounting for about 9.6% each.

Next, I'm going to deposit this precious 5200 yuan into ICBC. I use a three-year fixed term with an annual interest rate of 4.25%. After three years, when I take out the money, there will be interest of 663 yuan, so my principal and interest will be 5863 yuan.

Math diary 7 After school this afternoon, my mother took me to the supermarket to buy things.

The things in the supermarket are dazzling. My mother took me to the place where I bought bread, and bought four pieces of bread, each 5 yuan. Then, my mother and I bought three boxes of yogurt, each box of 20 yuan; I bought another barrel of potato chips, each barrel 10 yuan. We are ready to check out, and my mother said to me, "I will test you today, and you will pay the bill." I smiled and said, "Hee hee, it's a piece of cake. I just learned to multiply today! " "Say that finish, I told my mother fluently:" A * * is 4× 5 ~ 3× 20 ~ 1× 10 ~ 90 yuan. "Then I took out 90 yuan from my mother's wallet and handed it to the cashier. Aunt smiled and said to me: "Today, the audience is 10% off!" Say that finish, and took my 9 yuan money back. I stared at my mother in disbelief: I didn't calculate wrong. It's 90 yuan. How did it become 8 1 yuan again? Mom smiled and said, "A discount is a discount. A 10% discount means that we only need to pay 90% of the original price, 90×90%=8 1 (yuan), then we only need to pay 8 1 yuan. "

After listening to it, I suddenly realized: this is the meaning of discount, and the discount is also calculated by multiplication! Multiplication is so widely used!

Math diary 8 Last night, my grandmother and I went to buy watermelons. This time, my task is to bargain with melon farmers and buy delicious watermelons.

There is a row of stalls selling melons at the entrance of the community. I came to the first melon stall first, because it was my first time to buy watermelon independently. I asked her gently, "How much is the watermelon?" "Seven cents." I thought to myself: Why is watermelon so cheap? ! I said, "1 yuan can I buy two?" The melon farmer smiled and said, "Five or six dollars each. Do you want to buy two for a dollar? Seventy cents a catty. " "Oh." I feel particularly embarrassed. I suddenly found a melon stall selling yellow watermelons, which is my favorite. "Haha, this will help me out!" I immediately pulled my grandmother: "Grandma, let's buy yellow watermelons." Then I ran away as fast as I could.

This time, I have some experience and know what the melon farmers mean by 70 cents! I want to bargain with him at once. But grandma said I couldn't do it, so she bought two watermelons, but they were only fifty cents cheaper, that is, sixty-five catties.

After I sent the watermelon home, I was still unwilling and went to another melon stall myself. I successfully negotiated the price this time, and my performance was much better than grandma's: in the past, it was 70 cents a catty, but I cut it to 65 cents a catty and picked a watermelon, weighing 9 kilograms, which is 9x0. 65=5。 85 yuan, I had five smooth talks. 5 yuan, deal.

Buying melons this time is not a small gain!

On the day of math diary 9, I finished my homework very early. My mother came to me and said kindly, "Son, have you finished your homework?" I nodded my head. "Then let's play a game!"

Mother brought a round cardboard and fixed a rotatable pointer in the center of the cardboard with a nail. Then divide the circular cardboard into 24 grids on average, and write 1-24 numbers in each grid. "Mom, what are the rules of this game? Say it quickly! " I said I was in a hurry. "The rules of the game are very simple, that is, when the pointer turns to an odd or even grid, the next number must be added. If it adds up to an odd number, I win; if it adds up to an even number, you win. " Mom said with a sly smile.

I think this game is too simple. I have played it for more than ten times in a row. However, mom always wins. I thought hard and never thought of it. Mom smiled and asked, "Why does it add up to an odd number every time?" So, I racked my brains to think, and finally thought of it, and shouted: "Mom, you are so cunning. No matter which number you go to, adding the next number equals the singular number. That is, odd plus even equals odd. If the pointer points to an odd grid, then the next number must be even; If the pointer points to an even cell, then the next cell must be an odd cell. So no matter which grid you go to, the total number is odd. Mom, you won with this rule. "

In the world of mathematics, there are many wonderful laws everywhere. As long as we learn mathematics well and make good use of it, we can become small experts in mathematics!

Math diary 10 After school this afternoon, I had to "go to work" with my mother because I had a meeting with her company.

I got into the elevator and went to the 26th floor, where I saw a beautiful young aunt. Menstruation turned around and smiled and said to me, "You are so beautiful, little friend. How old are you this year? " I said, "I'm eight years old." Aunt, how old are you? I asked. My aunt said, "My age is multiplied by 2, minus 16, and then divided by 2 plus 8, and the result is exactly 38. Say, how old am I this year? " Wow! Dizzy! Dizzy! Is addition, subtraction, multiplication and division. I'm confused. I have no choice but to ask my mother. Mom said, "You can push it backwards!" I had a brainwave and soon had my own ideas. Well, I started with the result of 38: which number plus 8 equals 38? This number is 38-8 = 30; 30 is a number divided by 2.

Therefore, the number before dividing by 2 is 30× 2 = 60; 60 is a number minus 16. The number before subtracting 16 is 60+16 = 76; 76 is the age of the aunt multiplied by 2, and the age of the aunt is 76÷2=38 years old. Many things happen, and I finally understand. Ask aunt: "Are you 38 years old?" Aunt said happily, "You are so smart, that's right!" Through this incident, I not only learned the backward deduction method, but also learned the importance of learning mathematics.

Math diary 1 1 In today's math class, the teacher and we did an experiment. As soon as the class began, the teacher asked us to open our books and said that this class should talk about "synthesis and practice". As he spoke, he brought a balance, a box and a half nails, some rice and a box. Looking at these clothes, we don't know what medicine the teacher is selling in the gourd, so I wonder: Could it be weighing?

When the teacher correctly wrote "Weigh the total" on the blackboard, the students suddenly realized. The experiment began, and the teacher took out a paper box full of rice. "Students, guess how many meters there are?" The teacher asked. The students rushed to answer: "1000? 500? 20xx？” The teacher said, "Let's use experiments to calculate the total number of rice correctly." When he spoke, the teacher began to explain. In the first step, how many pieces 1 g of rice were weighed? As a result, 62 pieces 1 gram of rice were weighed on the balance. Step 2: Weigh the whole box of rice and put it on the balance, totaling 590 grams. The last step is to calculate the total, 590×62=36580, and finally you are done.

The second experiment is called nails. 1. How many nails are there in 50 grams? There were 20 nails, but the experiment ended in failure because there were too many nails in the box to weigh.

"Jingle bell ..." As soon as the bell rang, the experiment was over, but I still want to know more.

Math diary 12 We went to the library to watch the Pocket Science and Technology Exhibition this afternoon, so we had to take a taxi because my father was not at home.

There is a little black box in the middle of the front row of the taxi. After the driver's uncle put down the sign that said "empty car", there was a creaking typing sound in the box with several red numbers beating on it. I am curious. My mother told me it was called one meter. I asked my uncle again, how does it calculate the price? My uncle spoke patiently: "Every city has a starting price for taxis. Our starting price in Ningbo is 10 yuan, which can drive 3. 5 kilometers, plus fuel surcharge 1 yuan, is 1 1 yuan. " "That is more than three. How to calculate 5 kilometers? " Uncle said, "Within 10 km, every kilometer in 2 yuan, and outside 10 km, every kilometer in 3 yuan. How much should you pay if the car has just driven 10 km? " My mother and I count together, from 3. 5 km to 10 km: 10-3. 5=6。 5 (km), 6. 5×2= 13 (yuan), plus the starting price 1 1 yuan, you have to pay: 1 1+ 13=24 (yuan).

Mom said, "We used to take a taxi to grandma's house and spent 33 yuan. Can you calculate how far our home is from grandma's? "

I thought about it, 33 yuan > 24 yuan, and this distance definitely exceeds 10 km. Calculate the excess first, and then calculate the excess distance, 33-24 = 9 (yuan), 3 yuan after 10 km, 9÷3=3 (km), plus the previous 65438+.

Yes, I got it right! Students, will you forget?

Math diary 13 sister got married on the fourth day of the first month. Get up at seven o'clock in the morning and go to my sister's wedding by bus at half past eight on time. My mother suddenly asked me, "How long does it take you to brush your teeth, wash your face, eat breakfast and tidy up?" I thought, "I brush my teeth for 3 minutes and wash my face for 2 minutes." I can eat breakfast slowly for 30 minutes, help with the dishes 10 minutes, and finally pack things 10 minutes, 2+3+30+ 10 = 55 minutes. " So I quickly replied, "It's 55 minutes." Then, I brushed my teeth, washed my face, had breakfast, washed the dishes and cleaned up, and went to my sister's wedding place by car.

When I got on the bus, my mother asked me again, "It's about 20 kilometers from here to the destination. Suppose you walk 1 m, it takes two steps. If you walk, how many steps do you have to take? " 20km = 20000m, 20000m× 2 = 40000 (step). I said, "Mom has to walk 40,000 steps, right?" Mom said, "Yes."

After about 20 minutes, we arrived at our destination. The wedding starts at 9: 30, and there is a red envelope grab in the middle. Aunt Yi gave us 200 red envelopes. I grabbed 12 red envelopes, two of which were from 52 yuan and the rest were from 22 yuan. My mother tested me again: "How much did Yi * * test today?" 52×2+22× 10=324 yuan, and I happily replied, "Mom, I got 324 yuan today!" "I went on to say," Mom, I want to use this 324 yuan to buy things I like. "Mom said," Yes, but you should take care of the money and don't buy it indiscriminately. " I said, "mom, don't worry, I won't spend money indiscriminately." "

Today, I was very happy to grab the 12 big red envelope. When I performed on stage, my aunt gave me a big gift package, and the first answer got many small gifts. What a happy and interesting wedding!

Math diary 14 Last night, my grandmother and I went to buy watermelons. This time, my task is to bargain with melon farmers and buy delicious watermelons.

There is a row of stalls selling melons at the entrance of the community. I came to the first melon stall first, because it was my first time to buy watermelon independently. I asked her gently, "How much is the watermelon?" "Seven cents." I thought to myself: Why is watermelon so cheap? . I said, "1 yuan can I buy two?" The melon farmer smiled and said, "Five or six dollars each. Do you want to buy two for a dollar? Seventy cents a catty. " "Oh." I feel particularly embarrassed. I suddenly found a melon stall selling yellow watermelons, which is my favorite. "Haha, this will help me out." I immediately pulled my grandmother: "Grandma, let's buy yellow watermelons." Then I ran away as fast as I could.

This time, I have some experience, and I know what the melon farmers mean by seventy cents. I want to bargain with him at once. But grandma said I couldn't do it, so she bought two watermelons, but they were only fifty cents cheaper, that is, sixty-five catties.

After I sent the watermelon home, I was still unwilling and went to another melon stall myself. I successfully negotiated the price this time, and my performance was much better than grandma's: in the past, it was 70 cents a catty, but I cut it to 65 cents a catty and picked a watermelon, weighing 9 kilograms, which is 9x0. 65=5。 85 yuan, I had five smooth talks. 5 yuan, deal.

I got a lot from buying melons this time.

Math diary 65438+On Sunday, May 6th, on a sunny day after the final exam, Teacher Zhang sent a message: Please ask parents to bring their children to see the final exam results of mathematics. Mom and Dad read this message and sighed: "Yuan Yuan's final exam score may not be above 90!" I said to my parents, "impossible, impossible, mom and dad, don't lose confidence in me." I get more than 90 points in every exam! "

It must be above ninety ... "... The next morning, I took my father to school and hurried to the classroom of Class Two (Five). I saw Teacher Zhang in the classroom and smiled and said to Teacher Zhang, "Can Teacher Zhang find my test paper? Teacher Zhang said, "OK." After finding out the test paper, I took a closer look and got 99+ 10. I am very happy. Dad took the test paper in my hand, looked at it and explained it to me. "Xiaoli bought five lilies with 20 yuan money, and Xiaohong bought a rose with 8 yuan money. Who bought expensive flowers? How much is each branch? You write this way: 20/5=4 (yuan) 8-4=2 (yuan). This is what my father should do to me: 20/5=4 (yuan) 8-4=4 (yuan). Don't turn 8-4 into 8/4. Is this good? You are too careless! "

"Yuan Yuan can't even count 8-4. Might as well go to the first grade. Too sloppy! " Teacher Zhang said. I bowed my head in shame. Dad looked at my score and said happily, "Yes, I got 99 points. If this question is not sloppy, it will be 100. Work hard and try to get 100 next time! " I said to my father, "Well, I'll try." Next semester, I will do: listen carefully in class, raise my hand actively, get 95 points or more in the exam, revise my homework on time, think independently, and be a good student who is good at learning.