Nowadays, many primary school students often encounter the phenomenon of meeting but not being right, or being right but not simple, or being right but not fast, and not being rigorous and complete in expression. I often hear some teachers or parents or students themselves say: alas! This problem could have been done, but I made a mistake because of carelessness. It seems that an unintentional sentence can excuse the arithmetic error. I think: carelessness itself is a manifestation of poor computing ability. Understanding carelessness from this perspective is more conducive to cultivating and improving students' computing ability.

Computing ability is one of the three basic abilities that need to be cultivated in primary school mathematics teaching. It is a combination of logical thinking ability, computational knowledge, and methods and skills to deal with quantitative relations. It can't exist and develop independently, but it is a comprehensive mathematical ability formed by mutual infiltration and support with memory ability, understanding ability, expression ability and spatial imagination ability. The basic requirements for computing power are correct, fast and simple.

Some common carelessness is mainly manifested in the following aspects:

First, primary school students' understanding of knowledge is relatively general.

The perception of primary school students is generally general and not detailed enough, especially in the lower grades. For example, when learning the addition and subtraction of two-digit numbers, 65 is often copied from 56 by mistake, and sometimes it is copied from the draft to the exercise book, and the movement will change, and 0.23 1 is copied into 0. 123. In addition, primary school students' vision is selective, and some novel and interesting parts come into view first, thus covering up other parts. For example, when calculating 200+ 10-200+ 10, many students calculate 0. Students pay too much attention to the subtraction of two identical numbers and ignore the operation order.

Second, primary school students' attention range is relatively narrow.

Pupils' attention is not easy to concentrate, and their attention range is not wide enough. When they are asked to pay attention to two or more objects at the same time, it is often easy to lose sight. Such as calculation: 150+ 16? 5-22= 150+80=230-22=208 Students fall 22 in the second step of calculation, and write 22 in the third step to form an inequality.

Third, primary school students are easily disturbed by mindset.

In terms of calculation, the original calculation rules interfere with the mastery of the new calculation rules. For example, when learning decimal addition and subtraction, some students always align the decimal point at first, but due to the influence of integer addition and subtraction, they still align the last decimal place. When you are a beginner in decimal subtraction, if the decimal part is not reduced enough, you should borrow 1 of the integer part and add it according to the denominator of the decimal part and the decimal part. However, some students are disturbed by the law of integer subtraction. No matter what the denominator of the topic is, they will borrow 1 as ten, and the result is wrong.

1, pay attention to the understanding and mastery of basic knowledge.

Concepts, formulas and rules are the basis of operation. Without a solid foundation, it is difficult to operate accurately, let alone quickly. Attention should be paid to stimulating students' interest in learning, strengthening the teaching of knowledge generation process, so that students can clearly understand the formation process of concepts and the derivation process of conclusions, and make clear what conclusions are, what are the conditions for the conclusion to be established, and in what scope it is applicable. For those related knowledge, confuse concepts, formulas, rules, etc. , but also use lists, charts and other effective ways to compare and analyze, find out their similarities and differences. We should also pay attention to exploring the methods of memory and carry out effective memory.

2. Pay attention to the cultivation of thinking quality.

Mathematics is the gymnastics of thinking. Thinking ability is the core of intelligence, and the quality of thinking reflects the level of thinking, which directly affects the speed and success of operation. Therefore, strengthening the cultivation of thinking quality is very important to improve computing ability. Thinking quality mainly refers to the agility, flexibility, profundity, extensiveness, innovation and criticism of thinking. Therefore, in the process of mathematics teaching, on the one hand, we should pay attention to exposing the thinking process of teachers, students and experts (textbook editors) so that students' thinking activities can be fully developed; In addition, students should master the basic thinking methods, that is, observation, comparison, analysis, synthesis, abstraction and generalization; Thirdly, we should pay attention to strengthening thinking training, especially the analysis of right and wrong cases. Wrong questions are rare targeted thinking training materials, which can play a very good role in this respect after processing.

3. Pay attention to the cultivation of non-intellectual factors.

Many operations involve certain knowledge, and some deformation and reasoning are carried out, especially in advanced mathematical operations. A problem is often not calculated in three or two steps, and some problems are more complicated to operate. It is necessary to make judgments at any time during the operation and make appropriate adjustments. Therefore, in teaching, we should pay attention to cultivating students' tenacious learning will and perseverance, and cultivate students' independent thinking spirit and good operating habits. Educate students to have three minds, that is, to be full of confidence before operation and believe that they have the ability to solve this problem; Be careful in the operation, and carefully write or draw every data, symbol and figure. When you haven't got the correct result for a while, you should be patient, carefully start from the examination of the questions, analyze the ideas and carefully check every step. Don't be impatient. Usually, we should pay attention to neatness and standardization in our homework, form the habit of careful inspection and examination, and strive to improve the accuracy of our calculations.

4. To cultivate the ability of calculation, we should also pay attention to teaching students some oral calculation, mental calculation and simple calculation methods, and teach students how to check whether the numbers are correct. For example, to solve an equation, the obtained solution should be substituted into the original equation for testing. In order to check whether the operation result is correct, it can be used to check whether there is a digital copy error or an operation error in the operation process step by step, and sometimes it can be used as a chart to verify.