On Sunday night, the north wind is blowing, so I can't go out for a walk. Just when I was bored, my grandmother took out playing cards and wanted to play blackjack with me.
Grandma took Wang and Wang away and divided the remaining 52 cards into two parts, each with 26 cards in her hand. It is stipulated that each player should play two cards, calculate who can work out the fastest by the method of addition, subtraction, multiplication and division, and then give the other player four cards. In the end, whoever loses the card in his hand will win.
At cards, the nurse took out two fives and I took out two ones. I got the answer at a glance: 5 * 5 = 25 25-1= 24 24 *1= 24, so grandma had to hold four cards in her hand. The second time I took out five or six, grandma took out seven or eight, and I was stumped at once. Looking at grandma's self-confidence, I was even more anxious. I put four cards around me and suddenly had a brainwave. It turns out that 7-5 = 26 ÷ 2-3 * 8 = 24 is finally worked out!
Ah, twenty-four o'clock is really interesting!
My home is about 3500 meters away from Guanqian Street. It takes us about 30 minutes to travel by car on weekends, that is to say, we drive about 120 meters per minute on average. In addition, you need to add the time to find a parking space and pay the parking fee. But once my grandmother took me to ride a battery car, which only took 20 minutes. In other words, I rode about 175 meters per minute on average. In contrast, the speed of cycling is 1 of the driving speed. About five times. So, I said to my mother, "If we travel by bike, we can not only save time, but also save parking fees and gas bills." My mother smiled and praised me for being thoughtful.
This unintentional calculation made me understand why we should advocate green travel! Really save time and money.
Mathematics is everywhere in life. As long as you use your head, you will find many ways to save time and money. I like math, so I must study hard and apply what I have learned to real life.
I want to invent something called micro air conditioner in the future, because our children especially like to play. After the fight, you will sweat a lot and your face will be red. Like a red apple, they will keep panting and shouting "hot ~ hot!" " So if I want to invent it in the future, it will be much better, and I won't be tired with it every day. It will be as big as an eraser, and it can be put anywhere, in a bag, or hung with a rope around its neck, so that you can play as much as you want without sweating.
If I want to know how to do it, I can do it now.
Once, the hunter kidnapped Snow White in the forest. Snow White, who just woke up, couldn't help looking around when she saw a strange environment.
Seeing that Snow White refused to eat poisonous apples, the hunter said angrily, "Snow White, I want to ask you a question. If you get it right, I will let you go. If you answer wrong, hum, you have to eat apples. How about it? " Snow White nodded.
The hunter said, "There is a man who counts 5 vertically. When 1 is added with two decimal places, the addition becomes a negative sign and 26 is obtained. Can you work out the correct result? "
Snow White wrote on her hand and suddenly said loudly, "Is it 7.44?"
The hunter was surprised and asked, "How did you work it out?" Snow White replied, "The wrong formula is" 5. 1-() 2.6, so let's calculate the number in brackets first and use 5. 1-2.6 equals 2.34, so 2.34+5. 1 equals 7.44, so the answer is 7.44. "
The hunter suddenly knew the trick, nodded inexplicably and replied happily: "I keep my promise, you can go." "
Snow White went home happily.
One morning in the summer vacation, my mother and I were having breakfast when we suddenly found that all the side dishes for breakfast were finished, so I suggested that my mother go to the supermarket to buy some side dishes such as mustard tuber.
When I arrived at the supermarket, I began to buy the side dishes I wanted. My mother gave me a task, that is, let me pick them out with pocket money and finish the checkout.
I carefully observed the price of the side dishes I chose, among which the price of mustard tuber was 1.5 yuan per package, and I was going to buy three packages. So, I silently calculated an account in my mind. Because I haven't learned multiplication with decimal point, I want to remove the decimal point and then use multiplication 65,438+05× 3 to calculate, and add a decimal point to the last 45, and the result is 4.5 yuan.
I went to the cashier, took out 5 yuan money from my coin purse and gave it to the cashier, who gave me 0.5 yuan. I silently checked the change of 5.0-4.5=0.5 yuan. It seems that the cashier did not get the wrong number.
I went home with my mother with three packs of mustard tuber.
In today's math class, Miss Huang asked us to do a thinking question. As soon as I saw the problem, I immediately began to bury myself in writing. I think I must do it right this time. If I do well, I will have the opportunity to participate in the Qiao Yuan Cup at school. How eager I am to participate, as long as I work hard. ...
I thought about it. Can't I share it? I tried, but I couldn't. Can I add auxiliary lines? But no matter how I add it, I just can't. Just when I was desperate, I had a glimmer of hope in my heart. I can try, but I still can't.
"Time is up!" Teacher Huang said that Teacher Huang asked Xu Kedi to come up and explain. She drew a triangle on that figure. Later, after listening to her explanation, I finally understood that the midpoint is in the drawn triangle! My initial thoughts were all wrong. I said to myself, "Why didn't I think it was so simple?" But later, I quickly convinced myself.
Although I didn't work out this problem, I said to myself, "believe in yourself, that's right!" I was wrong this time. There will always be one next time! "
Speaking of mathematics, I have a lot to say. This is my worst subject. I think learning mathematics requires good thinking and a cool head. Another interesting thing for me is to study math.
One day when I was at school, I met a big problem. Here's the theme. On a large cylinder, two cylinders are placed to obtain their surface area. When I was still calculating their surface areas one by one, and then subtracting the relevant parts, my classmates had finished the calculation. I was shocked. Why can he calculate so fast? After class, I went to the classmate and asked him, "How can you work out that problem so quickly?" "Because you didn't use the right method, let me teach you. You can only calculate the surface area of the largest figure, and then calculate the side area of the small figure. It is very convenient to add up. " She said with a smile, I was shocked again that there was such a clever plan.
Therefore, learning mathematics is also very important. If you encounter problems that you can't meet, you must ask them in time until the meeting, so as to improve your grades and make it easier for us to learn math.
I recommend another method to you, that is, listen carefully in class, although this is only what students must complete, and few people can really complete it perfectly.
Let's cheer together.
There are many technological things around us, such as rice cookers, computers, televisions and electric lights. Our science is really getting better and better, which is created by everyone's efforts. Daquan science brings us many benefits and makes our life better!
The efforts of scientists have not been in vain!
The former yellow mud road → mud road → cement road → has evolved into today's asphalt road, which shows that our traffic has improved. The previous moonlight → fireflies → oil lamps → kerosene lamps → evolved into today's electric lights, indicating that our fire lamps have improved. Now there is a new thing, as follows. Recently, I found that there would be cars running through traffic lights on our road, so I installed a camera. Once the car runs a red light, it will be fined 200 yuan. That thing will film the scene!
My uncle is an example because of the curiosity of my cousins. Now we can all cross the road safely!
How convenient!
We have cars on the road, ships on the sea, planes and rockets in the sky ... we have got rid of the "two-legged vehicle", which is a scientific progress. Science will bring us a better life!
I think everyone has raised goldfish. Have you ever thought about the water problem of goldfish? Today, I had a whim to raise goldfish with tap water just released.
Today, I went to the flower and bird market and bought some goldfish. At home, I filled the fish tank with tap water, without baking soda, pure tap water, put the goldfish in the water, put away the fish food, and ***8 fish. The first day, 1 fish died. I looked at the fish food and thought, is this normal? Raise fish. The next day, all seven fish died. I thought: this is not normal. How did the goldfish die so fast this time? After I buried the goldfish, I looked it up on the Internet. Only then did I know that there was bleach in tap water and no oxygen. No wonder people leave tap water for two days before raising goldfish. If I had known to check directly on the Internet, I would have wasted eight lives. Next time, I know that it is necessary to put tap water for a few days before keeping goldfish, or put baking soda in the water to generate oxygen, so that goldfish can live longer.
I understand from this incident that both fish and people need oxygen to survive!
On Saturday, my parents and I traveled to Hangzhou. How can you travel without water? So, my father and I went to buy water together.
When I arrived at the store, I said loudly to the waiter aunt, "Aunt, I want to buy three bottles of water." "Dad pointed to the sign hanging on the wall. I looked in the direction of my father's finger, only to see the sign saying: "Renovation clearance, buy 2 pieces, get 1". I think: buy 2 get free 1, 2+ 1 = 3 bottles, then I only need to buy 2 bottles! I said to my aunt, "Aunt, I only need to buy two bottles. "Aunt smiled and gave me three bottles of water, the price of each bottle of water is 1 50 yuan. I bought two bottles of water, namely: 1. 5 yuan+1. 5 yuan = 3 yuan, I can buy three bottles of water with 3 yuan money, which is cheaper than usual 1. In 5 yuan, the average price of a bottle of water is 1 yuan. I gave my aunt a 5 yuan note and my aunt gave me two one-dollar coins. My father and I left happily.
Mathematics is all around us. Let's look for mathematics in life!
Small composition composition 1 1 hands are stained with oil, which is difficult to wash. Some people will think of scrubbing with gasoline. Because gasoline is a very good solvent, it is very easy to dissolve all kinds of oil, so it is natural to handle this kind of oil stain on your hands, which is much more labor-saving than washing with water.
The skin on our hands is covered with a thin layer of oil, which can moisturize and protect. It is precisely because gasoline is very easy to dissolve oil, so when you scrub your hands with gasoline, the oil on your hands is gone, and the oil on the surface of your hands is dissolved by gasoline, so you are "washed" clean. Not only that, because the molecules of gasoline are very small, it will push luck into the skin and "pull out" the fat in the surface cells of the skin, taking it with it. Therefore, if you often scrub your hands with gasoline, the skin on your hands will lose the protection of sebum, become rough, dry, and sometimes dry, causing bacterial infection. Moreover, gasoline also contains benzene, toluene and other organic substances, which are toxic to human body. Regular contact with gasoline is not only irritating to the skin, but also very harmful to human health.
Therefore, if you get oil on your hands, you can wipe off some oil with paper first, then wash it with soap or detergent several times, and you can also clean the oil.
A few days ago, my mother bought a pot of bright flowers from the market. Although not very beautiful, it is a plant worthy of appreciation. Its leaves are small, but many, very lush. I watched it every day, and suddenly one day, I found some of its leaves withered. I couldn't help but be surprised and call my mother in a hurry. As a result, my mother took some egg shells from the kitchen and put them in flowerpots. Suddenly, a series of questions popped up in my mind-what is the function of putting egg shells? ...
A few days later, a miracle happened, the withered leaves disappeared and the flowers regained their former glory. In order to solve the doubts in my heart, I went to consult the relevant information and learned that there are residual egg whites in the empty eggshells that have just been knocked open, which will be used as fertilizer after being slowly absorbed by the soil. Fertilizer is good for the growth of flowers. For slow-growing flowers and trees, put a few empty eggshells in the flowerpot, so you don't have to worry about excessive fertilization. In addition, it can also reduce the acidity of soil and promote the growth rate of flowers and trees.
It seems that more observation and more brain gain is not small!
Composition composition 13 once in an Olympic math class, the teacher gave a topic, "Xiaohong made pancakes with a pot and only put two cakes at a time. It takes 2 minutes to fry a cake. (It is stipulated that both parties need 1 minute). How many minutes does it take Xiaohong to fry three cakes? I think: the first pot takes 2 minutes. Ok, it takes 2 minutes to change another one that is not fried, and 2+2 = 4 (minutes). But the teacher said, "Pay attention to saving time. There are two cakes in front of you and only 1 cake in the back. This is a waste of electricity. Think again. " The teacher said, take out three boxes as cakes, and then take out 1 book as a pot. The teacher asked me to put two cakes on the pot. 1 minute later, turn one over, take one out, and then put the third one in the pot. 1 min later, one is ready to be taken out, the second is put into the pot, the other is fried, and the third is turned over. 1 minute will be fine. So 1+ 1+ 1 = 3 (minutes)
There is mathematics everywhere in our life, waiting for us to discover it. Arrange your time reasonably and don't waste it.
One day, I was playing a game and met a challenge. As long as the topic is done correctly, I will get the corresponding reward. The topic is like this: starting from 1+2+3+ ... 100 =? I don't know when to add this. I quickly asked my father, who taught me a good way: for example, if you add 1 to 6, you can form 1+6 = 7, 2+5 = 7, 3+4 = 7, plus three 7s or 3x7, the number is 2 1. The calculation method is that the first number 1 and the last number 6 are added to get 7, and then multiplied by half of the last number, that is, multiplied by 6 ÷ 2 = 3, 3× 7 = 2 1, which is much more convenient. I tried to calculate that from 1 to 10, it is1+10 =1,10 ÷ 2 = 5,/kloc-0. Then 1 plus 100 is1+100 =10/0/,100 ÷ 2 = 50,10.
Haha, addition becomes multiplication, fast and accurate. Mathematics is really wonderful, and there is no end to mathematics. Mathematics is really a happy paradise!
15 science has a peculiar charm and a magical power. It is ubiquitous and often exists in our lives.
One day, my mother wanted to use a drink bottle and let me wash it. I washed the bottle with warm water, poured out the water and tightened the lid. After a while, I suddenly found the bottle was flat! I was surprised and asked my mother why. My mother smiled and said to me, "Go and find the answer yourself." . So I went to read a book, looked it up on the Internet, and finally found the answer. It turned out that hot water heated the air in the bottle, and the air expanded, which led to the expansion of the bottle. When the temperature of the air in the bottle drops, it shrinks again. At this time, the air pressure in the bottle is lower than that outside the bottle, so the air pressure outside the bottle deflates the bottle. Haha, I see, so this is the principle that air expands with heat and contracts with cold.
There is science everywhere in life. As long as we pay more attention, we will find the footprint of science and let science serve us.