1, to talk about the principles and rules of liquidation, principles and rules are the basis of calculation: the correct operation must be based on a thorough understanding of the principles, and students can remember the principles clearly in their minds, so they can be methodical when doing four calculation problems. The mathematical theories that pupils encounter are: the synthesis and decomposition of numbers within 10, the method of adding and breaking ten, the concept of adding the same number, the counting method of decimals, the concept of numbers, the meaning and nature of decimals, the change of decimal size caused by the movement of decimal position, the changing law of product and quotient, the meaning and nature of fractions, the concept of decimal unit, the relationship between fractions and division, and the concept of fractions and general fractions.
These basic knowledge should be clearly explained to impress students, so as to play a positive role in transferring new knowledge. For example, it is very important to know the law of decimal size change caused by decimal position movement. It is used when explaining the calculation rules of decimal multiplication and division and when converting decimals and percentages to each other. When explaining the calculation rules of addition, subtraction, multiplication and division of fractions, it is also inseparable from the concept of fractional units. If students can master these two parts of knowledge skillfully, they can learn the four operations of decimals and fractions smoothly.
2. It is necessary to clarify the order of elementary arithmetic: the operation order refers to the operation at the same level from left to right. In the formula without brackets, if there is addition, subtraction, multiplication and division, multiplication and division must be calculated first, and then addition and subtraction must be calculated; If there are parentheses, use the number of parentheses first, then the number of parentheses. The operation order of decimal and fractional elementary arithmetic is exactly the same as that of integer elementary arithmetic, so it is very important to clarify this operation order.
3. Clarify the meaning of the law of operation: primary school textbooks mainly talk about the exchange law and combination law of addition, and a property of subtraction: "A number MINUS the sum of two numbers is equal to this number MINUS two addends in turn." And the commutative law, associative law and distributive law of multiplication. These laws are applicable to the operation of integers, decimals and fractions at the same time, and are widely used. When explaining, students should first understand the meaning of these laws. It is difficult for students to master the nature of subtraction and the distribution law of multiplication and division. In teaching, we can cite familiar examples and draw some intuitive charts to illustrate them. On the basis of students' understanding, remember the meaning of law. In the fourth and fifth grades, they should be required to express the law in letters.
4. Strengthen the teaching of basic knowledge and the training of basic skills: In elementary arithmetic, an important link to strengthen basic training is to strengthen the teaching and practice of oral arithmetic. Oral calculation is the basis of written calculation. The skill of written calculation is the development of oral calculation, which is based on the rules of written calculation and after several oral calculations. Take 987×786 as an example, it needs 9 multiplications and 14 additions. It can be seen that there are errors in oral calculation and errors in written calculation. Therefore, not only the basic training of oral arithmetic in middle and low grades should be sustained, but also the senior grades should pay equal attention to it with the expansion and deepening of the learning content. This will not only help students to consolidate concepts and rules in time, increase the density of classroom teaching and improve their computing ability, but also cultivate students' thinking agility, attention and memory by guiding them to think actively and use knowledge flexibly in oral arithmetic training.
6. Organize exercises in a planned way: In order to improve students' computing ability, besides paying attention to the teaching of arithmetic and rules, the teaching of elementary arithmetic progression and the teaching of arithmetic rules, it is also very important to organize exercises in a planned way.
Improving students' computing ability is a meticulous and long-term teaching work. In addition to the above work, we should also pay attention to the guidance of students. In class, problems in students' calculation can be found and solved in time through students' answering questions, oral calculation, blackboard writing performance or written homework, so that students' mistakes can be eliminated in the bud. It is also very important for teachers to carefully correct homework, analyze the causes of errors, find out the rules of errors, and pay attention to cultivating students' good habits of examining, doing and searching questions.