Grade five math diary 1. It's very hot at noon today. The sun burns the earth like a big fireball. Cicada can't stand the sun, so she has to hide in the trunk and complain.
My sister and I came back from crazy play outside, so hot that we wanted to eat some fruit to quench our thirst. It happened that my aunt took out five attractive peaches from the room. My sister and I stared at the peaches on the plate, and everyone wanted another one. Aunt saw it and encouraged us to use math knowledge flexibly to have a competition-"outsmart peaches". The rule is: whoever gets the last peach will get two at a time.
My sister started first. Without thinking, she picked up two peaches and chewed them with relish. My head was running at full speed, and suddenly a coup came to me. I didn't take two first, like my sister did, but I took a Momo, and my sister was secretly pleased. I eat peaches slowly. This is because my sister has finished eating a peach, and I only ate half. When she finished eating one and a half peaches, I also finished eating the peaches in my hand. So, I picked up the two peaches left on the plate with lightning speed, shook my fingers smartly in front of her and said, "Little sister, if you want to hit me, read more books for a few years!" " Then he moved a chair and sat down, munching on peaches.
Hmm! This peach tastes really good!
Grade 5 math diary 2 65438+Saturday, February 6th, is my grandmother's birthday. On my birthday, my father sent me to play badminton first. Learn badminton at10: 00-11:50 in the morning. There are 15 students in our badminton class. At the beginning of each class, Mr. Bi will let us warm up first, and each of us will play 500 balls. Then, we will pick up 50 badminton, and each person will play 3 groups, and each group will play 5 times. After that, we 1 line up, with 5 people in each line, and practice the swing. There are four steps in the swing. Whoever fails to catch the net five times during spiking will do 100 squats. I did 20 squats this time, only 1 time when I didn't surf the internet, and the most students did 100 squats. We had a good time.
1 1:50 class dismissed. Father picked me up on time and drove me to the hotel. The hotel has three floors, and we eat on the second floor. Grandma invited two tables of guests, 20 people. Mom bought a big cake. She divided the cake into 20 parts on average, and everyone could eat one twentieth of the cake. However, my brother Niu Niu wants one. What shall we do? Mom doesn't share much cake, and nobody has it. Niu Niu asked for it again, which embarrassed me. Suddenly,
I have a good idea. My mother doesn't like cakes. I gave Niu Niu one twentieth of my mother's cake, and now Niu Niu has a new one, which is one twentieth of the cake. Niu Niu is very happy, and I am also very happy, because I solved the problem with the scores I learned.
Math diary, Grade 5 3 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, study hard, master more math skills, apply what you have learned and solve problems around you.
The fifth grade math diary 4 "Moore Manor" is a game that our primary school students like very much, which can make us relax while studying nervously. At the same time, I also found that Moore Manor also contains a lot of mathematical knowledge, and playing games can also improve our mathematical level.
There is no furniture in my house in the game. In the game magazine, I found a set of beautiful small furniture, worth 3300 mol beans. However, I only have 3000 moles of beans. What should I do to buy this furniture?
So I used my brain and found that the mole beans deposited in the bank have interest, and the interest rate is 3% per day. That is to say, the daily interest on 3,000 moles of beans deposited in the bank is: 3,000 x 3% = 90 moles of beans.
A day later, my deposit became: 3000+90=3090 mol beans;
Two days later, my deposit became: 3000+90×2=3 180 mol beans;
Three days later, my deposit became: 3000+90×3=3270 mol beans;
Four days later, my deposit became: 3000+90×4=3360 mol beans.
That is, after the fourth day, my savings can pay for furniture!
I think there is mathematics everywhere in my life, including games. As long as you use your head, many small problems in life can be solved by mathematics!
On the evening of the 5th grade, math diary saw a math problem in the book of Olympic Mathematics. There are three times as many apple trees as pear trees in the orchard. Master Wang fertilizes 50 apple trees and 20 pear trees every day. A few days later, all the pear trees were fertilized, but the remaining 80 apple trees were not fertilized. Excuse me: How many apple trees and pear trees are there in the orchard?
I am not intimidated by this question, which can stimulate my potential best. I think the apple tree is three times as big as the pear tree. If two kinds of trees are to be fertilized on the same day, Master Wang will fertilize 20X3 apple trees and 20 pear trees every day. In fact, he only fertilizes 50 apple trees every day, which is 10, and the last 80 trees. Therefore, Master Wang has been fertilizing for 8 days. 20 trees a day, 8 days is 160 trees. According to the first condition, we can know that there are 480 apple trees. This is to solve the problem with the idea of hypothesis, so I think the hypothesis method is a good way to solve the problem.
By solving this difficult problem, I understand that no matter what I do, I should be careful and think more, otherwise, even if I master the method of solving problems, the result will still be wrong.
When math diary, a fifth-grade student, finished school in the afternoon, the class teacher assigned us a homework, 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 scratched my head and shook my head while reasoning. ...
Finally, small eyes. 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 7, Grade 5 This morning, I was doing my math summer homework. I wrote and wrote. Unfortunately, I met a very difficult problem. I've thought about it for a long time, but I can't figure it out. The problem is this: the circumference of a rectangle is 280 cm and the width is 40 cm. Take one side of this rectangle as the bottom, make a triangle with a height of 50 cm, and find the area of this triangle.
I read it and thought: Yes! This question is still a bit difficult! But no matter how hard it is, you have to survive! At this time, I asked my father for help. Father patiently told me how to solve it. Before my father finished, I suddenly realized that the problem was so simple, and the formula was: 280 ÷ 2 =140 (cm); 140-40= 100 (cm); 100×50÷2=2500 (square centimeter).
I was ecstatic to see that I finally got the wrong question again and again. In fact, any topic is not that difficult, just don't think about it. As long as you think, any topic is very simple.
School is about to start, and my homework is basically finished, so it's not too much trouble. My winter vacation plan has been completed very well. Let's have a new semester, fly high!
Grade 5 math diary 8 This morning, I was doing my math summer homework. It says, unfortunately, I have encountered a very difficult problem that I haven't thought of for a long time. The problem is this: the circumference of a rectangle is 280 cm and the width is 40 cm. Take one side of this rectangle as the bottom, make a triangle with a height of 50 cm, and find the area of this triangle.
I looked at it and thought: Yes! This question is still a bit difficult! But no matter how hard it is, you have to survive! At this time, I asked my father for help. Father patiently told me how to solve it. Before my father finished, I suddenly realized that the problem was so simple. The formula is: 280÷2= 140 (cm) 140-40= 100 (cm).
100×50÷2=2500 (square centimeter).
I'm glad to see that I finally got the wrong question over and over again. In fact, any topic is not that difficult, just don't think about it. As long as you think, any topic is very simple.
School is about to start, and my homework is basically finished, so it's not too much trouble. My winter vacation plan has been completed very well. Let's fly high in the new semester!
The ninth corner painting of math diary's fifth grade needs to be discussed directly, otherwise I will tell you!
There are two ways to draw an angle, one is to draw with a protractor, and the other is to draw with a triangle.
Then let's talk about the method of drawing angles with a protractor. 1 First draw a ray so that the center of the protractor coincides with the endpoint of the ray, and the zero scale line coincides with the ray, and then point a point on any scale line of the protractor. If the opening is to the right, look at the scale of the inner ring; If the opening is to the left, look at the scale of the outer ring. Take the endpoint of the drawn ray as the vertex, align the vertex with the point just drawn with the ruler of the ruler, and then draw a ray. This corner is finished.
There is another way, that is, the angle formed by putting together the angles of the triangle ruler. For example: 75 = 45+30; 120 = 90+30. This method is very simple, that is, draw one corner of a triangle first, then draw one side of the other corner of another triangle close to the side of the corner just drawn, aim at the top corner, then draw the other side, and finally mark the degree and angle symbols, and an angle is completed.
This is an angle diagram. Have you learned everything?
The fifth grade math diary 10 20xx 10 is sunny on Wednesday.
Simple multiplication operation
Yesterday, Teacher Liu reviewed the simple operation for us.
When Mr. Liu asked a question, we copied it in our notebook and worked out the answer in a simple way. Teacher Liu also asked a group of six students to do the questions on the blackboard in turn. When we finish writing, we compare them with the students' answers on the blackboard to see who is wrong and who is right. We don't usually comment on the right. If a student makes a mistake, we will be a little teacher, point out where the classmate made a mistake and analyze the reasons for his mistake. So we practiced until class was over. Many students have done problems on the blackboard and got exercise.
Let me teach you simple arithmetic.
For example: 25× 12×4 We can change the positions of 12 and 4 by using the multiplicative switching law. 25×4 is exactly 100, and then 100× 12 is equal to 1200. Isn't that soon? Another example: 3× 125×8 We can also use the multiplicative associative law. Let's say 125×8, 125×8 is exactly 1000, and 1000×3 is 3000. Another example: 25×(4+8) We can use multiplication and division. Use 25×4 for 100, then use 25×8 for 200, and finally use 100+200 for 300.
Can these methods work out the answer quickly? Have you learned everything I taught you?
Math diary 1 1 Grade 5 Recently, we studied the recognition of scores, and the recognition of scores is not just a few scores. Instead, use charts to represent scores. For example, a circle is divided into four pieces on average, and each piece is a quarter of the circle. We also learned about true scores and false scores. False fraction means that the denominator is less than the numerator or the denominator is the same, and true fraction means that the denominator is greater than the numerator. So the false score is greater than 1 and the true score is less than 1.
For example, there are two identical graphs, and each graph is divided into two parts equally. The first figure draws two squares (half), and the second figure only draws one square (half). These two numbers can be described as true points, that is, four points are only one point, two-thirds are described as false points, and one and a half points can also be described. This is a fraction, and a fraction is a combination of an integer and a true fraction.
False scores can be turned into scores, and scores can also be turned into false scores. How to turn a false score into a score? Just divide its numerator by its denominator and read it from top to bottom. For example, three out of seven is two and a third. The quotient is an integer, the divisor is the denominator, and the remainder is the numerator, so it is two and a third.
We also studied fractions and division. Divided by the divisor, the dividend of the divisor is equal to the dividend of the divisor.
Math diary, Grade 5 12 This morning, I was doing my math homework for the summer vacation. I wrote and wrote. Unfortunately, I met a very difficult problem. I've thought about it for a long time, but I can't figure it out. The problem is this: the circumference of a rectangle is 280 cm and the width is 40 cm. Take one side of this rectangle as the bottom, make a triangle with a height of 50 cm, and find the area of this triangle.
I read it and thought: Yes! This question is still a bit difficult! But no matter how hard it is, you have to survive! At this time, I asked my father for help. Father patiently told me how to solve it. Before my father finished, I suddenly realized that the problem was so simple. The formula is: 280÷2= 140 (cm) 140-40= 100 (cm).
100×50÷2=2500 (square centimeter).
I was ecstatic to see that I finally got the wrong question again and again. In fact, any topic is not that difficult, just don't think about it. As long as you think, any topic is very simple.
School is about to start, and my homework is basically finished. Actually, it's not much trouble. My winter vacation plan has been completed very well. Let's have a new semester, fly high!
Math diary Grade 5 13 came across such incredible data in a book today: "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?"
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, and got10737418.24cm.. 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, such amazing data are everywhere in mathematics in ordinary life, as long as you have a pair of eyes that are good at discovering.