2. To cultivate students' good habit of examining questions, we should not only know the known conditions, but also see the symbols accurately; (When copying formulas, you can ask them to read the formulas while copying the questions, and you can take the form of silent reading. After copying, check if there are any mistakes. If in this case, students still copy the wrong symbols and numbers, we should pay attention to the state of these children who copy the wrong numbers and symbols, and also prescribe the right medicine according to their personality characteristics and pay some patience. Secondly, train students to master basic formulas and theorems skillfully, so that they can master basic knowledge well and the accuracy of calculation will be greatly improved.
Elementary arithmetic is a difficult content in calculation teaching, and it is also one of the questions with the highest error rate among students. Therefore, the examination teaching of elementary arithmetic requires students to do the following:
(1) "Look"
"Look" means to look at the numbers in the topic first. There will be several operation symbols; Let's first look at the characteristics and internal relations of operational symbols and data. Such as 405× (3076-2980)+2 136 ÷ 89. The result should be: ① There are five numbers; ② There are four operations; (3) including parentheses; ④ It is an integer elementary arithmetic problem with brackets. Another example is 3.68× [1÷ (2.1-2.09)]+0.6. The result should be ① a number containing 5; ② There are four operations; (3) contains parentheses; (4) The mixed problem of four decimal points is in brackets.
(2) "fixed"
"Fixed" is to determine the operation sequence after observing the whole topic. That is, what is important first, what is important again, and what is important again. You can mark the order by drawing lines, such as: 405× (3076-2980)+2136 ÷ 89 │ └ └ └ ┬ ┘ ┘ ┘.
(3) "Thinking"
"Thinking" refers to the relationship between numerical characteristics and operation in analysis problems, associating with relevant operation rules and properties, and then performing operations. Such as: 405× (3076-2980)+2 136 ÷ 89. Although there is no simple calculation problem for this problem, the bracket part and division can be calculated simultaneously, that is, the quotient of the difference between 3076-2980 and 2 136÷89 can be calculated simultaneously.
Sometimes, according to the characteristics of data, the original structure is decomposed, combined and deformed by 15 1 to realize simple calculation. For example, the combination of 4-+2.375+5-+7.75 is (4-+7.75)+(24845.375+5-). In the examination teaching of calculation problems, special attention should be paid to cultivating students' habit of analyzing specific problems and their ability to use knowledge flexibly, so that students can calculate calculation problems correctly and quickly.
3. Cultivate students' habit of self-examination, whether it is a simple question or a complex question, they should have the habit of checking after finishing. I usually follow the practice of the fifth grade group and summarize their self-study methods: three checks and three comments: one is to check the number symbols, the other is to check the calculation method, and the third is to check whether the final result is the simplest score. If it is literal, you can add four checks: unit and answer.
4. Finally, cultivate students' habit of summarizing and reflecting, reflect and summarize some mistakes in the calculation process in time, and avoid making the same mistakes many times. Therefore, we can do the same kind of questions again for their mistakes. Make it deeper.