Bitcoin 1115 event
Publish: 2021-05-01 23:40:39
1. In June 2011, Symantec issued a warning that botnets are participating in bitcoin; mining & quot; In the middle. This can take up the computing power of the victim's computer, consume extra power, and cause the temperature of the host to rise. Later that month, ABC found an employee using the company's server to mine
some malware also make great use of the parallel computing power of graphics cards. In August 2011, botnet of bitcoin mining was discovered, and Mac OS X infected by Trojan horse was also discovered to mine bitcoin.
on June 19, 2011, security vulnerability of mt.gox (Magic: abbreviation of the gathering online exchange) bitcoin trading center caused the price of 1 bitcoin to drop to 1 cent (although other transactions were not affected). The reason is that a hacker stole the user's mtgox certificate from the computer infected with the Trojan horse, so he transferred bitcoin to his own account and sold it, resulting in a large number of "ask" requests at that price. A few minutes later, mtgox shut down and cancelled the abnormal transactions in the hacking incident, making the price of bitcoin rebound back to $15. In the end, the bitcoin exchange rate went back to what it was before the crash. Accounts equivalent to more than $8750000 were affected
in July 2011, the operator of bitomat, the world's third largest bitcoin trading center, announced the loss of access rights to the wallet.dat file that records 17000 bitcoins (about 220000 US dollars). At the same time, announced the decision to sell services to make up for the loss of users
in August 2011, mybitcoin, one of the processing centers of common bitcoin transactions, announced that it had been attacked by hackers and shut down. Involving 49% of customers' deposits, more than 78000 bitcoins (then equivalent to about $800000) are missing
in early August 2012, bitconica was sued in the San Francisco court for damages of about $460000. In 2012, bitconica was attacked twice by hackers, accused of ignoring the security of customers' funds and forging withdrawal applications
in late August 2012, bitcoin savings and trust was shut down by its owner, leaving about US $5.6 million in debt. At the same time, he was accused of operating the Ponzi scheme. In September 2012, the securities and Exchange Commission began to investigate the case
in September 2012, bitfloor trading center was also hacked, and 24000 bitcoins (about US $250000) were stolen. Bitfloor was suspended. Bitfloor resumed operations in the same month, and its founder said he had reported the theft to the FBI and that he was planning to compensate the victims, but the compensation schele was unclear
in June 2011, a hacker transferred 25000 bitcoins into his account, which is equivalent to 500000 US dollars. The whole transaction could not be traced. Although the owner of bitcoin announced the theft on the Internet, it was useless. The hacker became the first thief of bitcoin
in 2012, 46703 bitcoin worth US $228845 was stolen e to the disclosure of the super management password of the server of the website hosting provider linode. More than 43000 stolen bitcoins belong to bitcoinica, a bitcoin trading platform. Another 3094 bitcoins are owned by Marek palatinus, a Czech programmer. Gavin Andersen, the chief bitcoin programmer, also lost his five bitcoins.
some malware also make great use of the parallel computing power of graphics cards. In August 2011, botnet of bitcoin mining was discovered, and Mac OS X infected by Trojan horse was also discovered to mine bitcoin.
on June 19, 2011, security vulnerability of mt.gox (Magic: abbreviation of the gathering online exchange) bitcoin trading center caused the price of 1 bitcoin to drop to 1 cent (although other transactions were not affected). The reason is that a hacker stole the user's mtgox certificate from the computer infected with the Trojan horse, so he transferred bitcoin to his own account and sold it, resulting in a large number of "ask" requests at that price. A few minutes later, mtgox shut down and cancelled the abnormal transactions in the hacking incident, making the price of bitcoin rebound back to $15. In the end, the bitcoin exchange rate went back to what it was before the crash. Accounts equivalent to more than $8750000 were affected
in July 2011, the operator of bitomat, the world's third largest bitcoin trading center, announced the loss of access rights to the wallet.dat file that records 17000 bitcoins (about 220000 US dollars). At the same time, announced the decision to sell services to make up for the loss of users
in August 2011, mybitcoin, one of the processing centers of common bitcoin transactions, announced that it had been attacked by hackers and shut down. Involving 49% of customers' deposits, more than 78000 bitcoins (then equivalent to about $800000) are missing
in early August 2012, bitconica was sued in the San Francisco court for damages of about $460000. In 2012, bitconica was attacked twice by hackers, accused of ignoring the security of customers' funds and forging withdrawal applications
in late August 2012, bitcoin savings and trust was shut down by its owner, leaving about US $5.6 million in debt. At the same time, he was accused of operating the Ponzi scheme. In September 2012, the securities and Exchange Commission began to investigate the case
in September 2012, bitfloor trading center was also hacked, and 24000 bitcoins (about US $250000) were stolen. Bitfloor was suspended. Bitfloor resumed operations in the same month, and its founder said he had reported the theft to the FBI and that he was planning to compensate the victims, but the compensation schele was unclear
in June 2011, a hacker transferred 25000 bitcoins into his account, which is equivalent to 500000 US dollars. The whole transaction could not be traced. Although the owner of bitcoin announced the theft on the Internet, it was useless. The hacker became the first thief of bitcoin
in 2012, 46703 bitcoin worth US $228845 was stolen e to the disclosure of the super management password of the server of the website hosting provider linode. More than 43000 stolen bitcoins belong to bitcoinica, a bitcoin trading platform. Another 3094 bitcoins are owned by Marek palatinus, a Czech programmer. Gavin Andersen, the chief bitcoin programmer, also lost his five bitcoins.
2. From May 12, bitcoin blackmail computer virus broke out all over the world. At present, 16 hospitals across the UK have been attacked on a large scale, and many Chinese universities have been recruited. Hackers blackmail users for ransom by locking computer files, and only charge bitcoin
in this global computer virus incident, mobile China also received a blackmail. Fortunately, the machine that received the email was a testing machine, which did not affect us. However, it's different for college students in the graation season. The thesis is locked, which is related to graation. So in the face of this outbreak of blackmail virus, how should we deal with it and what protective measures should we take<
first of all, let's understand the characteristics of this virus
the computer virus initiated by hackers will encrypt a large number of files on the system into files with. Onion suffix. After poisoning, they are required to pay bitcoin ransom to decrypt and recover the files, causing serious losses to personal data, and anti-virus software cannot decrypt these encrypted files. But we must not listen to the hacker's so-called "give money to decrypt" saying, because hackers do not necessarily keep their promises, in addition, bitcoin is expensive, and it is also a large number for ordinary users< Secondly, we need to pay attention to the background of the virus outbreak.
according to the domestic experts, according to the network security agencies, this is a virus attack event launched by lawless elements using the "eternal blue" leaked from NSA hacker's weapon library“ "Eternal blue" will scan windows machines with open 445 file sharing port, without any user operation. As long as the machine is turned on and connected to the Internet, criminals can plant blackmail software, remote control Trojan horse, virtual currency mining machine and other malicious programs in computers and servers
e to the previous outbreak of worms using port 445 in China, operators have blocked port 445 for indivial users, but the ecation network has no such restriction, and there are still a large number of machines exposing port 445. According to the statistics of relevant institutions, at present, more than 5000 machines in China are attacked by NSA "eternal blue" hacker weapons every day, and the ecation network is the hardest hit area
What are the coping methods
1. Close port 445, and you can search and query by yourself
2. At present, Microsoft has released a patch ms17-010 to fix the system vulnerability of "eternal blue" attack. You can install this patch for your computer as soon as possible
as for XP, 2003 and other Microsoft machines that no longer provide security updates, microblog professionals recommend using "NSA Arsenal immunity tool" to detect whether there are vulnerabilities in the system, and close the ports affected by the vulnerabilities, so as to avoid being attacked by blackmail software and other viruses
in this global computer virus incident, mobile China also received a blackmail. Fortunately, the machine that received the email was a testing machine, which did not affect us. However, it's different for college students in the graation season. The thesis is locked, which is related to graation. So in the face of this outbreak of blackmail virus, how should we deal with it and what protective measures should we take<
first of all, let's understand the characteristics of this virus
the computer virus initiated by hackers will encrypt a large number of files on the system into files with. Onion suffix. After poisoning, they are required to pay bitcoin ransom to decrypt and recover the files, causing serious losses to personal data, and anti-virus software cannot decrypt these encrypted files. But we must not listen to the hacker's so-called "give money to decrypt" saying, because hackers do not necessarily keep their promises, in addition, bitcoin is expensive, and it is also a large number for ordinary users< Secondly, we need to pay attention to the background of the virus outbreak.
according to the domestic experts, according to the network security agencies, this is a virus attack event launched by lawless elements using the "eternal blue" leaked from NSA hacker's weapon library“ "Eternal blue" will scan windows machines with open 445 file sharing port, without any user operation. As long as the machine is turned on and connected to the Internet, criminals can plant blackmail software, remote control Trojan horse, virtual currency mining machine and other malicious programs in computers and servers
e to the previous outbreak of worms using port 445 in China, operators have blocked port 445 for indivial users, but the ecation network has no such restriction, and there are still a large number of machines exposing port 445. According to the statistics of relevant institutions, at present, more than 5000 machines in China are attacked by NSA "eternal blue" hacker weapons every day, and the ecation network is the hardest hit area
What are the coping methods
1. Close port 445, and you can search and query by yourself
2. At present, Microsoft has released a patch ms17-010 to fix the system vulnerability of "eternal blue" attack. You can install this patch for your computer as soon as possible
as for XP, 2003 and other Microsoft machines that no longer provide security updates, microblog professionals recommend using "NSA Arsenal immunity tool" to detect whether there are vulnerabilities in the system, and close the ports affected by the vulnerabilities, so as to avoid being attacked by blackmail software and other viruses
3.
The virus in the "bitcoin virus" incident is known as "ransomware". By encrypting the files in the victim's computer, you can't open them completely to ask for ransom. This is a virus attack launched by lawless elements by using "eternal blue" leaked from NSA hacker's weapon library. It does not need any operation of users. As long as it is turned on and connected to the Internet, lawless elements can implant blackmail software into computers and servers
What's more terrible is that this is just the beginning. Now this blackmail virus has spread to all over the world, including many colleges and universities in China. You can see many students on the Internet showing pictures of their computers being attacked. I have to say that hackers are really well intentioned, even in simplified Chinese
4.
Bitcoin is a kind of network virtual electronic currency, and its price has experienced roller coaster like ups and downs. It has no physical support, to put it bluntly, a string of computer code. Personally, I think this is a very unreliable thing. The Internet bubble is very big. In November 2013, the price of bitcoin once reached a high level of 8000 yuan / piece. Subsequently, the central bank, together with five ministries and commissions, issued the notice on preventing bitcoin risks, and the price of bitcoin plummeted. Now the price of bitcoin is more than 2300 yuan / piece
Jingxuan finance didn't you send a lot of articles a few days ago. China is now investigating bitcoin. Crash
5.
According to reports, at about 20 p.m. on May 12, some domestic college students reported that their computers were attacked by viruses and their documents were encrypted. The attacker claimed to pay bitcoin to unlock
according to the network security agency, this is a virus attack event launched by lawless elements using the "eternal blue" leaked from NSA hacker weapon library“ "Eternal blue" will scan windows machines with open 445 file sharing port, without any user operation. As long as the machine is turned on and connected to the Internet, criminals can plant blackmail software, remote control Trojan horse, virtual currency mining machine and other malicious programs in computers and servers
6. Bitcoin extortion virus is basically sent with virus bound, so don't open files with uncertain sources, and back up important files in time. Although the anti-virus effect is not great, we should try our best to upgrade anti-virus and operating system patches in time. These measures are not only to prevent bitcoin virus, but also to prevent more viruses
7. What is bitcoin< p> bitcoin is a digital currency with a total amount of 21 million , which has the characteristics of decentralization, globalization and anonymity, just like the Internet
transferring bitcoin to the other end of the earth is as simple, low-cost and unlimited as sending e-mail
As a result, bitcoin is used in cross-border trade, payment, remittance and other fields
first: benefiting from the loose monetary policy of the Federal Reserve,
suffered from the COVID-19 pandemic this year. In order to solve the liquidity crisis and stimulate the economy, the Fed injected a large amount of liquidity into the US dollar, causing huge fluctuations in the global financial market, including the digital money market. P>
second: the occurrence of COVID-19, the hedging attribute of bitcoin
COVID-19 epidemic has swept across many countries in the world, and has also had a great impact on enterprises and investment circles. p>
in the Research Report of grayscale investment, it is mentioned that two thirds of the respondents who have invested in bitcoin in the past four months said that the new coronavirus epidemic affected their decision to invest in bitcoin
8.
At present, it is certain that its price will continue to increase. After all, there are many financial institutions supporting the stability of the currency price
there are too many uncertain events in 2020, such as epidemic, "3.12", WiFi, filecoin main network delay, US presidential election, etc., while the certain events include Ethereum 2.0 online, bitcoin price rise, etc
why is the rise of bitcoin price a deterministic event
This is undeniable, so it has become the most certain thing at the beginning of 2021. At present, it is certain that its price will continue to grow. After all, there are many financial institutions supporting the stability of the currency price< br />9. The cultivation of computational ability is an important task in primary school mathematics teaching. The level of a person's computing ability is the embodiment of his thinking agility and thinking flexibility in computing, which reflects the level of his basic mathematical quality. The level of computing ability not only affects students' academic performance, but also directly affects students' intellectual development, and also has a direct impact on students' future study and work. In the primary school stage, the main purpose is to cultivate students' ability to calculate integers, decimals and fractions, and to achieve correct and rapid calculation. At the same time, the method is required to be reasonable and flexible. How to cultivate and improve students' computing ability to meet the above requirements
in this paper, I would like to talk about some superficial understanding of this problem< First, we should fully understand the importance of developing computing ability
one of the aims of primary school mathematics teaching is to cultivate students' computational ability, and teachers must have enough understanding. Some teachers don't pay enough attention to the cultivation and improvement of students' computing ability, and they don't let students find the rules and interests of computing. This is a big obstacle to cultivate and improve students' computing ability, which must be removed. Computational ability is a necessary ability for students< Number and calculation are widely used in daily life, work and study. In the real world, from the perspective of mathematics, there are mainly three aspects: number, quantity and shape. However, measurement is inseparable from number and calculation, and the quantification of body size is inseparable from number and calculation. Therefore, number and calculation are the most basic tools for people to understand the objective world and the basic knowledge and skills that every citizen should master< Number and calculation are the basis for students to learn other mathematical knowledge and even other subjects. This part of the knowledge is not good, students can not enter the normal learning< Number and calculation play an important role in cultivating students' thinking ability. Mastering the process of number and calculation is also the process of cultivating students' abstract generalization ability. In this way, students also develop the ability of abstract generalization in the process of learning to master the knowledge of number and calculation
4. The teaching of number and calculation is concive to infiltrating the enlightenment ecation of dialectical materialism. The concept of number is graally formed and developed with the needs of human life and practice. When teachers want to teach the concept of number, the relationship between calculation method and calculation method, they can infiltrate the enlightenment ecation of dialectical materialism
Second, clarify the calculation theory and improve the teaching quality of calculation
in the teaching of calculation, teachers should pay attention to explain the principle of calculation and reveal the law of calculation, so that students can know what it is and why it is
1. The abstraction of arithmetic is a difficult point in primary school teaching. In teaching, we try to transform the abstraction into the concrete by means of visual demonstration, so as to make the arithmetic clear
2. Learn to operate with tools, explore and comprehend. Psychologists believe that thinking begins with action. To enable students to master mathematical knowledge and promote the development of thinking, it is necessary to build a bridge between image thinking and mathematical abstraction, and give full play to the role of learning tools. For example, if the students have difficulty in understanding the "method of making up ten" in addition within 20, we will ask them to come out with sticks to help them learn the calculation method of "making up ten" by playing with sticks
3. Contact with practice to deepen understanding. Using students' existing knowledge and experience to understand new knowledge is the main way to construct teaching knowledge structure. Properly using old knowledge in teaching, assimilating new knowledge through analogy, and realizing positive transfer of knowledge are concive to students' understanding of new knowledge and recognition of new knowledge structure. For example, when teaching the calculation method of decimal addition, we can use the rate relationship of RMB units that students are familiar with to explain the reason that decimal points must be aligned
4. Pay attention to perception and strengthen stimulation. For the parts that are easy to be ignored by students, we should pay attention to strengthen the stimulation intensity (such as emphasis on entering and leaving places, emphasis on the treatment of decimal points, etc.) to attract students' attention, leave students a clear and correct impression, and avoid and rece errors in future calculation
5. According to the characteristics that students are prone to illusion and thinking set, we should consciously differentiate and compare the similar concepts, rules and formulas, so as to promote the accurate differentiation of new and old knowledge
6. Practice in time to consolidate and improve. Carry out targeted exercises, strengthen the key points and difficulties in the calculation process, and strive to consolidate in class
7. Pay attention to feedback and correct in time. Timely feedback, find out the students' mistakes, help students analyze the reasons and correct the mistakes in time< Third, we should deal with the relationship between written and oral arithmetic
oral arithmetic is a kind of calculation method which can only calculate and get the results by thinking and language without any tools. It has the characteristics of fast and flexible
mental arithmetic is an important part of computing power. Oral calculation is the basis of written calculation and estimation. Both written calculation and estimation ability are developed on the basis of accurate and skilled oral calculation ability. Without a certain basis of oral calculation, the cultivation of written calculation and estimation ability becomes the water without source. In addition, mental arithmetic is widely used in daily life, proction and scientific research. Therefore, it is very important to insist on the training of oral arithmetic and listening arithmetic in teaching to improve students' computing ability
(1) oral arithmetic teaching must run through the whole process of primary school mathematics teaching. In the lower grades, basic oral arithmetic such as addition and subtraction within 20, multiplication within the table and division are arranged; The middle grade arranges some oral arithmetic which is the basis of written arithmetic and often used in daily life; In order to cultivate students' ability of using knowledge flexibly and their ability of oral calculation, senior students arrange some questions of using operation law to do oral calculation in exercises. Each teaching reference book puts forward the requirements for the oral arithmetic of this semester in stages. Teachers should make the cultivation of oral arithmetic ability to be implemented, and effectively improve students' oral arithmetic ability
(2) arrange oral calculation reasonably. In compulsory textbooks, the basic oral arithmetic, which is the basis of written arithmetic, is taught before written arithmetic, while some difficult but not the most basic ones are taught after written arithmetic, so as to further improve students' oral arithmetic ability. For example, addition and subtraction within 20 is an important foundation of addition and subtraction, and only oral arithmetic is taught. In addition and subtraction within 100, two digit addition, subtraction of one digit and integral tens, such as 27 + 6, 27 + 30, are the basis of both written and oral arithmetic. Therefore, this part of the content before the written calculation, only teaching oral calculation; It is more difficult for students to master double-digit plus or minus double-digit, so the first grade first teaches written arithmetic, and the second grade further requires oral arithmetic. In this way, students can not only learn written arithmetic, but also form a strong ability of oral arithmetic
(3) pay attention to the teaching of oral arithmetic. Oral examples should pay attention to the intuitive demonstration and operation to make students understand the calculation theory
(4) teach students oral arithmetic and develop their thinking. In order to improve students' ability of oral arithmetic, we should teach students correct methods of oral arithmetic. The methods are various, and we should guide students to choose the methods that they can easily understand and master. Never guide students to do oral arithmetic with the method of written arithmetic. Two digit addition: 28 + 37. I find that some students think like this: 8 + 7 = 15, indivial digit is 5, ten digit is 2 + 3 + 1 = 6, ten digit is 6. This is completely the idea of written calculation. In fact, you should think like this: 28 + 30 = 58, 58 + 7 = 75. You don't need to have a vertical pattern in your head
practice has proved that strengthening the training of oral arithmetic can not only improve the calculation level of students, but also develop their thinking ability< Fourth, encourage students to use simple algorithms to improve their ability and develop their thinking
simple calculation is a practical and effective method to improve students' calculation speed. Simple calculation often uses certain operation laws, such as addition calculation often uses addition exchange law, addition combination law, and multiplication exchange law, multiplication combination law, multiplication distribution law, etc. in multiplication calculation, some calculations are simplified from complex to easy. The study of simple calculation can not only improve the students' calculation speed, rece the calculation errors, but also help the development of students' thinking. Therefore, in the teaching process, teachers should strengthen the teaching of simple methods
in addition, let students remember some common data, which can simplify the calculation process and improve the calculation speed. I remember an ecator said that a person's memory before the age of 13 is the best. He can remember a lot of things at this stage. Although he doesn't know why and how, these things don't affect his memory. The unknown reasons of these knowledge will be solved with the growth of his age and the increase of his knowledge. Therefore, we should pay attention to the development of students' memory, especially before the age of 13. The content of calculation in middle and high grades is extensive, comprehensive and comprehensive. Some common operations are often encountered in real life. These operations have no specific rules of oral arithmetic, and must be solved by strengthening memory training. The main contents of my intensive training are as follows: 1) the square result of each number from 1 to 10 in the natural number; ② A method of oral calculation for the square result of two digit number of 5 on a digit; ③ Some specific calculation results, such as 125 × 8＝1000，25 × 4 = 100, 0.25 =, 0.75 =, 0.125 =, 0.375 =, 0.625 = etc. These special calculation results are frequently used in practice, homework and life. If we master and remember them skillfully, we can transform them into abilities, which play a good role in calculation and proce high efficiency< 5. Pay attention to cultivate the good habit of careful examination and calculation
the teaching of calculation also needs to train students to form the habit of careful examination and examination. Don't just shout "be careful!" to students, To teach methods, strict requirements, form habits, improve the accuracy of calculation
the new curriculum standard points out that we should pay attention to the cultivation of students' habit of inspection. Inspection is a good way, it can make people find their own mistakes in time and correct them in time. In the process of teaching, teachers should pay attention to strengthen the teaching of checking calculation, let students use different methods to test a problem, master the test method, and skillfully use this method to judge the correctness of the answers to similar problems
six relations between addition, subtraction, multiplication and division are often used in checking. The estimation is often based on the variation of proct and quotient. For example: according to the multiplier & gt; 1, proct & gt; Multiplicand (except 0); Multiplier = 1, proct = multiplicand; If the multiplier is less than 1, the proct is less than the multiplicand (except 0), you can judge which of the following questions is greater than the multiplicand, which is less than the multiplicand, and which is equal to the multiplicand: 8 × 、 nine × 、 one × 2、0.9 × 16、5 × 1、3 × 、 × 1 According to divisor > 1, quotient < divisor (except 0); Divisor = 1, quotient = dividend; If the divisor is less than 1, the quotient is greater than the divisor (except 0), it can be judged without calculation ÷ 14、8 ÷ 1 、21 ÷ 、 ÷ 7、2 ÷ 1、0.45 ÷ Is the quotient greater than the divisor, less than the divisor, or equal to the divisor< Sixth, enrich learning activities, be happy with teaching and learning, and stimulate students' interest
the calculation problem is composed of numbers and abstract operation symbols, which makes students easily feel irritable and tired. Therefore, teachers should
in this paper, I would like to talk about some superficial understanding of this problem< First, we should fully understand the importance of developing computing ability
one of the aims of primary school mathematics teaching is to cultivate students' computational ability, and teachers must have enough understanding. Some teachers don't pay enough attention to the cultivation and improvement of students' computing ability, and they don't let students find the rules and interests of computing. This is a big obstacle to cultivate and improve students' computing ability, which must be removed. Computational ability is a necessary ability for students< Number and calculation are widely used in daily life, work and study. In the real world, from the perspective of mathematics, there are mainly three aspects: number, quantity and shape. However, measurement is inseparable from number and calculation, and the quantification of body size is inseparable from number and calculation. Therefore, number and calculation are the most basic tools for people to understand the objective world and the basic knowledge and skills that every citizen should master< Number and calculation are the basis for students to learn other mathematical knowledge and even other subjects. This part of the knowledge is not good, students can not enter the normal learning< Number and calculation play an important role in cultivating students' thinking ability. Mastering the process of number and calculation is also the process of cultivating students' abstract generalization ability. In this way, students also develop the ability of abstract generalization in the process of learning to master the knowledge of number and calculation
4. The teaching of number and calculation is concive to infiltrating the enlightenment ecation of dialectical materialism. The concept of number is graally formed and developed with the needs of human life and practice. When teachers want to teach the concept of number, the relationship between calculation method and calculation method, they can infiltrate the enlightenment ecation of dialectical materialism
Second, clarify the calculation theory and improve the teaching quality of calculation
in the teaching of calculation, teachers should pay attention to explain the principle of calculation and reveal the law of calculation, so that students can know what it is and why it is
1. The abstraction of arithmetic is a difficult point in primary school teaching. In teaching, we try to transform the abstraction into the concrete by means of visual demonstration, so as to make the arithmetic clear
2. Learn to operate with tools, explore and comprehend. Psychologists believe that thinking begins with action. To enable students to master mathematical knowledge and promote the development of thinking, it is necessary to build a bridge between image thinking and mathematical abstraction, and give full play to the role of learning tools. For example, if the students have difficulty in understanding the "method of making up ten" in addition within 20, we will ask them to come out with sticks to help them learn the calculation method of "making up ten" by playing with sticks
3. Contact with practice to deepen understanding. Using students' existing knowledge and experience to understand new knowledge is the main way to construct teaching knowledge structure. Properly using old knowledge in teaching, assimilating new knowledge through analogy, and realizing positive transfer of knowledge are concive to students' understanding of new knowledge and recognition of new knowledge structure. For example, when teaching the calculation method of decimal addition, we can use the rate relationship of RMB units that students are familiar with to explain the reason that decimal points must be aligned
4. Pay attention to perception and strengthen stimulation. For the parts that are easy to be ignored by students, we should pay attention to strengthen the stimulation intensity (such as emphasis on entering and leaving places, emphasis on the treatment of decimal points, etc.) to attract students' attention, leave students a clear and correct impression, and avoid and rece errors in future calculation
5. According to the characteristics that students are prone to illusion and thinking set, we should consciously differentiate and compare the similar concepts, rules and formulas, so as to promote the accurate differentiation of new and old knowledge
6. Practice in time to consolidate and improve. Carry out targeted exercises, strengthen the key points and difficulties in the calculation process, and strive to consolidate in class
7. Pay attention to feedback and correct in time. Timely feedback, find out the students' mistakes, help students analyze the reasons and correct the mistakes in time< Third, we should deal with the relationship between written and oral arithmetic
oral arithmetic is a kind of calculation method which can only calculate and get the results by thinking and language without any tools. It has the characteristics of fast and flexible
mental arithmetic is an important part of computing power. Oral calculation is the basis of written calculation and estimation. Both written calculation and estimation ability are developed on the basis of accurate and skilled oral calculation ability. Without a certain basis of oral calculation, the cultivation of written calculation and estimation ability becomes the water without source. In addition, mental arithmetic is widely used in daily life, proction and scientific research. Therefore, it is very important to insist on the training of oral arithmetic and listening arithmetic in teaching to improve students' computing ability
(1) oral arithmetic teaching must run through the whole process of primary school mathematics teaching. In the lower grades, basic oral arithmetic such as addition and subtraction within 20, multiplication within the table and division are arranged; The middle grade arranges some oral arithmetic which is the basis of written arithmetic and often used in daily life; In order to cultivate students' ability of using knowledge flexibly and their ability of oral calculation, senior students arrange some questions of using operation law to do oral calculation in exercises. Each teaching reference book puts forward the requirements for the oral arithmetic of this semester in stages. Teachers should make the cultivation of oral arithmetic ability to be implemented, and effectively improve students' oral arithmetic ability
(2) arrange oral calculation reasonably. In compulsory textbooks, the basic oral arithmetic, which is the basis of written arithmetic, is taught before written arithmetic, while some difficult but not the most basic ones are taught after written arithmetic, so as to further improve students' oral arithmetic ability. For example, addition and subtraction within 20 is an important foundation of addition and subtraction, and only oral arithmetic is taught. In addition and subtraction within 100, two digit addition, subtraction of one digit and integral tens, such as 27 + 6, 27 + 30, are the basis of both written and oral arithmetic. Therefore, this part of the content before the written calculation, only teaching oral calculation; It is more difficult for students to master double-digit plus or minus double-digit, so the first grade first teaches written arithmetic, and the second grade further requires oral arithmetic. In this way, students can not only learn written arithmetic, but also form a strong ability of oral arithmetic
(3) pay attention to the teaching of oral arithmetic. Oral examples should pay attention to the intuitive demonstration and operation to make students understand the calculation theory
(4) teach students oral arithmetic and develop their thinking. In order to improve students' ability of oral arithmetic, we should teach students correct methods of oral arithmetic. The methods are various, and we should guide students to choose the methods that they can easily understand and master. Never guide students to do oral arithmetic with the method of written arithmetic. Two digit addition: 28 + 37. I find that some students think like this: 8 + 7 = 15, indivial digit is 5, ten digit is 2 + 3 + 1 = 6, ten digit is 6. This is completely the idea of written calculation. In fact, you should think like this: 28 + 30 = 58, 58 + 7 = 75. You don't need to have a vertical pattern in your head
practice has proved that strengthening the training of oral arithmetic can not only improve the calculation level of students, but also develop their thinking ability< Fourth, encourage students to use simple algorithms to improve their ability and develop their thinking
simple calculation is a practical and effective method to improve students' calculation speed. Simple calculation often uses certain operation laws, such as addition calculation often uses addition exchange law, addition combination law, and multiplication exchange law, multiplication combination law, multiplication distribution law, etc. in multiplication calculation, some calculations are simplified from complex to easy. The study of simple calculation can not only improve the students' calculation speed, rece the calculation errors, but also help the development of students' thinking. Therefore, in the teaching process, teachers should strengthen the teaching of simple methods
in addition, let students remember some common data, which can simplify the calculation process and improve the calculation speed. I remember an ecator said that a person's memory before the age of 13 is the best. He can remember a lot of things at this stage. Although he doesn't know why and how, these things don't affect his memory. The unknown reasons of these knowledge will be solved with the growth of his age and the increase of his knowledge. Therefore, we should pay attention to the development of students' memory, especially before the age of 13. The content of calculation in middle and high grades is extensive, comprehensive and comprehensive. Some common operations are often encountered in real life. These operations have no specific rules of oral arithmetic, and must be solved by strengthening memory training. The main contents of my intensive training are as follows: 1) the square result of each number from 1 to 10 in the natural number; ② A method of oral calculation for the square result of two digit number of 5 on a digit; ③ Some specific calculation results, such as 125 × 8＝1000，25 × 4 = 100, 0.25 =, 0.75 =, 0.125 =, 0.375 =, 0.625 = etc. These special calculation results are frequently used in practice, homework and life. If we master and remember them skillfully, we can transform them into abilities, which play a good role in calculation and proce high efficiency< 5. Pay attention to cultivate the good habit of careful examination and calculation
the teaching of calculation also needs to train students to form the habit of careful examination and examination. Don't just shout "be careful!" to students, To teach methods, strict requirements, form habits, improve the accuracy of calculation
the new curriculum standard points out that we should pay attention to the cultivation of students' habit of inspection. Inspection is a good way, it can make people find their own mistakes in time and correct them in time. In the process of teaching, teachers should pay attention to strengthen the teaching of checking calculation, let students use different methods to test a problem, master the test method, and skillfully use this method to judge the correctness of the answers to similar problems
six relations between addition, subtraction, multiplication and division are often used in checking. The estimation is often based on the variation of proct and quotient. For example: according to the multiplier & gt; 1, proct & gt; Multiplicand (except 0); Multiplier = 1, proct = multiplicand; If the multiplier is less than 1, the proct is less than the multiplicand (except 0), you can judge which of the following questions is greater than the multiplicand, which is less than the multiplicand, and which is equal to the multiplicand: 8 × 、 nine × 、 one × 2、0.9 × 16、5 × 1、3 × 、 × 1 According to divisor > 1, quotient < divisor (except 0); Divisor = 1, quotient = dividend; If the divisor is less than 1, the quotient is greater than the divisor (except 0), it can be judged without calculation ÷ 14、8 ÷ 1 、21 ÷ 、 ÷ 7、2 ÷ 1、0.45 ÷ Is the quotient greater than the divisor, less than the divisor, or equal to the divisor< Sixth, enrich learning activities, be happy with teaching and learning, and stimulate students' interest
the calculation problem is composed of numbers and abstract operation symbols, which makes students easily feel irritable and tired. Therefore, teachers should
10.
This big drop in bitcoin prices can be said to have directly led to the collapse of many people. And behind this slump, many people doubt whether there is someone behind bitcoin operating in the dark, controlling the price of bitcoin. Today, we will discuss whether there are hidden operations behind the 470000 people's explosion{ RRRRR}
Third, how to treat the black box operation behind
many people say that the transaction price of bitcoin is controlled by several groups. They control the rise and fall of bitcoin to keep their own funds rising. To tell you the truth, it's possible. As long as you have a lot of bitcoin, you can control the market. But to tell the truth, if we harvest leeks simply by controlling the market trend, it's a bit of a fuss for such a large amount of funds
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