Once, when I was analyzing the final examination paper of fourth grade mathematics, I found that "calculation" had the lowest score loss rate among all items, only 3.4%. This makes the average score of my class as high as 93.6, which is about 10 higher than that of the parallel class, and the loss rate of calculation items in the parallel class is about 16%. I also checked the math test paper analysis tables of grade three and grade five, and found that the failure rate of calculation problems was higher, about 2 1%, which led to their average scores not exceeding 90 points. Looking at the examination papers of all grades in primary schools, the proportion of questions related to calculation is about 85%. However, the failure rate of students' calculation has always occupied a considerable proportion. According to statistics, the average score of students' calculation is between 8- 15 (including the calculation error of the number of application questions). It can be seen that students' computing ability is generally low, which is of course related to the unstable age characteristics of students. However, it can be seen from this series of data that it is very important to cultivate students' computing ability and develop the habit of careful calculation in mathematics teaching. Based on my years of teaching experience, I would like to talk about my humble opinion on cultivating students' habit of careful calculation.

First, strengthen oral arithmetic training, focusing on the classroom

It is clearly pointed out in "Elementary Mathematics Teaching Syllabus" that in elementary arithmetic, written calculation is the key and oral calculation is the foundation, so we should pay attention to the basic training of oral calculation and cultivate students' computing ability. Oral calculation is not only the basis of written calculation, estimation and simple calculation, but also an important part of calculation ability. Qiu Zonghu, a famous expert in Mathematical Olympiad, pointed out: "If you want to learn mathematics well, you must first know how to calculate, and you must know how to calculate. The four operations of addition, subtraction, multiplication and division should be skilled and accurate. I can not only do mental arithmetic, but also do mental arithmetic. The heart is a kind of thinking ability. With good mental arithmetic, many problems can be worked out in your mind and you can think about problems anytime and anywhere. " Through the above explanation: oral calculation is the basis of all kinds of calculations. For example, "carry addition and subtraction within 20" and "add and subtract within 10" in senior one; "99 multiplication formula" in the second grade. These basic knowledge and students' proficiency are directly related to the speed of oral calculation and the level of calculation ability. For example, when writing "576+849", the knowledge of carry addition within 20 is used, and this knowledge point is used more than once, which shows that any written calculation problem is composed of several overlapping calculation problems. Another example is: when calculating "376×25" with a pen, both the formula of 99 multiplication and the formula of addition are used. If there is a problem in any link, it will lead to the wrong calculation result of the problem. This requires students to firmly grasp the basic knowledge of mathematics and take every step of calculation seriously.

At present, under the leadership of the head of the mathematics teaching and research group in our school, I insist on oral arithmetic training for 3 ~ 5 minutes before class, which has lasted for five years and achieved certain results. Through this activity, the speed of students' oral calculation is accelerated and the correct rate is improved. And award a "king of verbal calculation" every month to encourage other students to get the title of "king of verbal calculation" as soon as possible. The purpose of the activity is to improve students' oral arithmetic ability and lay a solid foundation for written arithmetic.

Similarly, I just took over a new class in Grade Four this year. After a week's observation, I found that three students still have this problem: on the first day, I found that a classmate miscalculated "1000-257", on the second day, I found that a girl miscalculated "13-5", and on the fourth day, I found that a girl miscalculated "8+3". I even found them snapping their fingers. In view of this situation, I can't talk about what I learned in Grade Two in class. I can only give them some guidance after class, contact their parents and tell them why their children are so slow in doing their homework. Every day, they go home to practice carry addition and subtraction within 20 and abdication subtraction. Don't let the children forget, try to recite carry addition and subtraction within 20. Only in this way can children's computing ability be improved, and of course their math scores will be improved accordingly. My parents listen to me and keep practicing every day. At present, the speed is faster than before, and the correct rate has also improved. But compared with other children, the response is still slow. However, I believe that practicing and not practicing are absolutely different. I firmly believe that "many things grind."

Second, strengthen the training of written calculation, focusing on peacetime.

Improving students' computing ability is not a problem that can be solved overnight, it needs us to start from usual.

First of all, we must make a clear calculation. If students want to calculate, they must be clear about how to calculate, that is, strengthen their understanding of laws and arithmetic. The Curriculum Standard for Primary Mathematics clearly points out that in teaching, students' sense of number should be further cultivated by solving practical problems and their understanding of the meaning of operation should be enhanced. Therefore, in teaching, teachers should use clear theories to guide students to master calculation methods, clarify and skillfully master calculation rules, operation properties, operation rules and derivation methods of calculation formulas, and cultivate students' awareness of simplification. For example, after students learn the properties of the equation, the key to solving the equation "99 ÷ x =- 1 1" is to multiply the x on both sides of the equation at the same time, so that the equation is still valid and can be transformed into the multiplication equation "99 =-1x". In order to save trouble, some teachers directly use the relationship between quantities in division to find the unknown X, that is, "divisor = dividend quotient". This is the method that students use before learning the properties of equations and equations. Now that you have learned new knowledge, you should use new methods to teach it. It is not easy for students to understand once they find that their teaching methods are wrong and change them. Psychologists point out that when they perceive new knowledge for the first time, the information entering the brain is not disturbed by proactive inhibition and can leave a deep impression on the students' cerebral cortex. However, if the first perception is inaccurate, the adverse consequences will be difficult to eliminate in the short term. Therefore, when we teach new calculations, the teaching of algorithms and arithmetic must be correct. This puts forward higher requirements for teachers: every teacher is required to be familiar with the new knowledge requirements of each textbook, design teaching plans according to the age characteristics and cognitive rules of students, and choose the best teaching methods to achieve the best teaching effect.

Secondly, the calculation can be carried out correctly. First of all, we should understand the types of calculation, such as: integer, decimal, addition, subtraction, multiplication and division of fractions and elementary arithmetic, which is easier to operate; Conversion of time, weight, length, area, volume and other units; Calculation of geometric figures such as length, square (body), triangle, parallelogram, trapezoid, circle, cylinder and cone; Calculation of ratio and proportion; Simplify evaluation, find the value of unknown, solve equation (group) and inequality (group); Interoperability among integers, decimals, fractions, fractions, percentages, etc. (including filling in the blanks and judging the calculations involved in the application problem). Next, I will focus on the calculation results. According to the teaching experience and students' competitive psychology in recent years, my methods are: rewarding and giving questions. The so-called reward means that in the usual homework, all the questions involving calculation, including the unit test paper, will be given an "excellent" as long as they are answered correctly. At the end of the semester, the teacher will count that if the number of "excellent" exceeds 20, the teacher will add 20 points to his final paper, and if the total score exceeds 1 10, there will be prizes. In order to reward those students who usually calculate more carefully; For students who are usually careless in calculation, the teacher will give them two other similar questions besides correcting them. The teacher should correct them carefully, otherwise it will be invalid. The purpose of the question is: first, let students form the good habit of calculating carefully for the first time; The second is to prevent some students from accidentally dealing with teachers when calculating. The teacher should patiently explain the mistakes in the calculation method and lead to the wrong results, and give similar topics to consolidate. Through the teaching verification in recent years, the method I adopted has achieved good results. I never ask students to revise it more than twice. I think similar problems will be done, then all the problems to be solved will be solved.

Third, work hard on topics that students are easy to confuse and make mistakes. For example, when students see "24×5", it is easy to calculate according to "25×4"; "54÷9" is regarded as "45 ÷ 9"; "0.7+3" is regarded as "7+3". It shows that students are easily influenced by fixed thinking and interfered by strong information. Another example is: "80-80 ÷ 8 → 80-80 = 0,0 ÷ 8 = 0", "72+28×18 → 72+28 =100,100×. In view of the above situation, teachers had better take the form of comparative exercises to let students distinguish themselves, so as to cultivate students' good habit of careful observation; Or often practice a similar topic to reverse students' wrong thinking. For example, when I taught the multiplication table and distribution method in the first volume of the fourth grade of Shanghai Education Publishing House, there were always students who made mistakes and the distribution was uneven. Some students are confused about multiplication and associative laws. In this case, I also use the method of comparison and regular practice. At present, the whole class has mastered it very well. In a word, improving students' computing ability will not happen overnight. The focus is on the usual training, appropriate methods and the cultivation of calculation habits.