I want a 5th grade math diary! Can t copy, it must be new Hurry!

Today, my mom and I went to the supermarket to buy something. The supermarket is crowded with people and a dazzling array of goods. Mom hurried to take me to buy what I needed.

We started by buying a watermelon. This watermelon costs 3 yuan a pound and weighs 4 pounds. Then we came to the meat seller.

The meat sells for 8 yuan a catty, and we bought 3 catties. Later we bought another carton of milk. There are 16 cartons of milk in a carton, and each carton is 3 yuan.

In the end we went to buy cookies and spent 15 yuan. When I was queuing up at the checkout, my mother said to me, "How much do you want to pay?"

I thought about it, watermelon 3 * 4 = 12 yuan, meat 8 * 3 = 24 yuan, milk 16 * 3 = 48 yuan, take 12 plus 48 first, exactly 60 yuan, plus 24 yuan equals 84 yuan, oh, by the way, there are biscuits, 84 + 15 = 99 yuan. I asked my mom to get a $100 bill ready. When we checked out, the salesman aunt counted it, and sure enough, it was 99 yuan, which was the same as my calculation.

Mom complimented me on how smart I was. I said to my mother: Then you will call me next time you buy something!

The harvest of this purchase is really not small. Not only did I know some daily necessities, but I also used the math knowledge I usually learned. It turns out that math is all around us.

;The spear is broken and the amount can reach Penguin Spicy'3-;Sou Ke Fini Day Female Stingy Oh ** Crazy, Birthday Women's Day Color Oh Boulder Man Fever Body Sister Ah Rate Destruction Withering and Decaying Li Ruiri.

(1) 10 bottles of drinks, one of which is spoiled (slightly heavier), weigh it with a scale, at least weigh ( ) times to find out the spoiled bottle.

2) There are 13 parts, 12 of which are of the same quality, and the other is a defective product, which is lighter than the qualified product.

3) There are 9 bottles of tablets, one of which is missing 4 tablets, and weigh it on a scale, at least ( ) times to ensure that this bottle of tablets can be found.

4) A village needs to plant trees on both sides of a 200-meter path, and plant one tree every 5 meters (both ends should be planted), and a total of ( ) saplings are needed.

5) There are 27 bottles of water with the same appearance, of which 26 bottles are pure water and one bottle is salt water.

6) There are 5 shuttlecocks, 4 of which are of the same quality, and the other is missing a shuttlecock, and the balance scales can find this shuttlecock at least ( ) times.

Math diary. Also heard for the first time.

Saturday, December 6 The weather is fine.

Today is Saturday, and after finishing our homework and going shopping with my mother, we came to Jusco Island in Oriental Plaza. Since it is a weekend, there are a lot of people in the mall.

We first came to the food shelves and picked out two packets of potato chips, each for yuan. Then we came to the place where stationery was sold. I saw a book printed with Mickey on it for sale, so I bought 4 at once, each yuan.

Then I also selected 3 signature pens, each for 1 yuan. After the purchase, my mom and I went to the checkout line. As I walked, I calculated how much money I used today:

Multiplying by 2 equals 7, and 7 plus multiplying by 4 equals 9 ......When I walked to the checkout machine, I just finished the calculation: I had a total of 12 yuan today. It seems that the knowledge I learned in math class is quite useful, even the decimal multiplication test I just took last month, and I got 95 points.

Today at noon, I was doing my math summer homework. Writing and writing, unfortunately encountered a difficult question, I thought about it for a long time and didn't come up with a reason, this question is like this:

There is a cuboid with the product of the two areas on the front and above being 209 square centimeters, and the length, width, and height are all prime numbers. Find its volume.

When I saw it, I thought, "That's a really hard question!" Only the product of the two surface areas is known, and the volume must also know the length, width, and height, and it doesn't hint at all. How do you get started?

Just as I was scratching my ears and cheeks in a hurry, a colleague of my mom came. He first taught me to use equations to solve, but I was not very familiar with this method. So, he taught me another way:

List the numbers first, then exclude them one by one. We first listed a number of numbers according to the requirements of the question, such as prime numbers such as , and then we started to exclude, and then we found that there were only two numbers left, 11 and 19.

The sum of the edges (and the lengths are prime). So, I began to tell which of the two numbers was which.

In the end, I got the result, which was 374 cubic centimeters. My equation is: 209 11 19 19 2 17 11 2 17 374 (cubic centimeters).

Later, I used what I learned this semester: decomposing prime factors to solve this problem, and the result was exactly the same.

After solving this problem, I was happier than anyone else. I've also learned that mathematics is full of mysteries waiting to be discovered.

A certain year, a certain month, a week, baix

Today, my mother told me to go to the mall to buy something, zhi

Reluctantly, the DAO went.

When I arrived at the mall, I didn't care about my mother, and rushed to the snack area to choose the snacks I wanted to eat. However, there was nothing delicious to eat, so I chose three packs of spicy and looked at the price by the way. Both packs are RMB, and the other pack is RMB2, for a total of 5 RMB.

I was just about to join my mother, but suddenly I thought that my refill was gone, so I had to buy a few pens. When I arrived at the place where stationery was sold, I picked it for a while and chose a pen that I thought was good, which was not expensive and was 2 yuan.

When he was about to look for his mother, he found that his mother was not far away, so he ran over to meet him and walked to the cash register together.

I was a little tired when I came home after a walk around the supermarket, but there was a lot of harvest at least snacks to eat, although it cost 7 yuan to go around. But I still have homework to write, and that's all for it.

There may be some things that are not very good, and I need to revise them slightly when I write them, I hope it will be useful to you.

You can write about buying things in life, the percentage of big questions in the test paper, questions about the distance (for example, you can make assumptions, "I walked home at a speed of 50 meters per minute and asked the distance between my home and my position at the moment), etc., and I should write in combination with what I have learned.

If you want to write a little deeper, you can write about the ** problems in the math book.

Mathematics is everywhere, there are a lot of mathematics around us, mathematics is indispensable, otherwise it will bring all kinds of inconvenience to life, let us look for mathematics together, explore mathematics.

Circle", we can see it everywhere, moon cake boxes, tea cans, and medicine boxes, aren't the bottom surfaces all round? They are not sold quickly, and they are called cylinders as a whole. Picking up these cylinders, you may think, why make the bottom surface round?

Why not make rectangles, squares? I used to doubt it, but now I can help you solve it!

If you make a box, a cube, and a cylinder with the same material, and then you calculate the volume, and we will find that the cylinder is the largest, the cube is the second, and the cuboid is the smallest. At this time, I understood, in order to save materials, I made these boxes round, so that the volume was also expanded.

That's the benefit of aid.

(4*82-254) 2=37pcs.

Yuan 500 3 = 166 remainder 2, the 500th position is 9

The sum of the first 500 digits = (2+9+6)*166+2+9=2833 If team B plants x trees per hour, then team A plants trees per hour.

5 (x + solution gives x = 14.)

Team B planted 14 * 5 = 70 trees, Team A planted trees = 14 * stools, the unit price of stools was X yuan, and the unit price of chairs was Y yuan.

5x+3y=135

2x+3y=99

Solution: x=12, y=25

The unit price of the stool is 12 yuan, and the unit price of the chair is 25 yuan.

Xiao Ming's house is located at a distance of x meters from the school.

x/60-4=x/80+6

Solution x=2400

Xiao Ming's house is 2,400 meters away from the school.

x+y=82 2x+4y=254 x=37 (chicken) y=45 (rabbit).

10x-6x= x=yuan.

500 3= Yes 9 (2+9+6)*166+2+9=28335x+3y=135 2x+3y=99 x=12 (stool) y=25 (chair).

x 60-4=x 80+6 x=2400 (m) Buy a Casio calculator The direct solution of the equation system Shenma.

In the evening, I saw a problem in the Olympiad book: the apple trees in the orchard were three times the size of the pear trees, and Master Wang fertilized 50 apple trees and 20 pear trees every day, and after a few days, all the pear trees were fertilized, but there were still 80 apple trees left unfertilized. Excuse me:

How many apple and pear trees are there in the orchard?

I wasn't intimidated by the question, the puzzle piqued my interest. I think that apple trees are three times the size of pear trees, and if two trees are to be fertilized on the same day, Master Wang should fertilize "20 3" apple trees and 20 pear trees every day. In fact, he only fertilized 50 apple trees every day, 10 of which were missing, and finally a total of 80 of them were missing.

20 pear trees a day, 160 pear trees in 8 days, and according to the first condition, we can know that there are 480 apple trees. This is to solve the problem with a hypothetical idea, so I think the hypothesis method is really a good way to solve the problem.