First, close to life and feel the valuation close to life. In the past, teachers always attached great importance to the accuracy and proficiency of students' written calculations, and students lacked estimation consciousness and estimation methods. But in daily life, it is estimation that is more widely used than written calculation. In order to strengthen students' estimation consciousness and cultivate students' estimation ability, we must first change students' attitude towards estimation in specific situations, correctly understand and experience the practical value of estimation, and change "unwilling to estimate" into "like to estimate". At the beginning, if you don't feel the practical value of estimation, students will find it useless to learn estimation. It is better to calculate accurately, so there is no way to stimulate students' curiosity. In fact, estimation, as an important mathematical thinking method and mathematical ability, can be seen everywhere in our daily life and is widely used. The key is whether you have found it carefully. The so-called estimation refers to the approximate extrapolation used when it is impossible or unnecessary to make accurate calculation and judgment in calculation and measurement. Estimation should cultivate students' knowledge and understanding of the generality and integrity of calculation or measurement results, and make reasonable judgments and inferences about logarithmic relations and spatial forms, which can improve students' ability to deal with and solve practical problems. For example, estimate the cost of shopping in a supermarket, estimate the area of a room, estimate the cost of traveling abroad, how many spectators can a stadium hold, how many eggs can be weighed in 2 kilograms, and estimate how many gold medals China will win in the Athens Olympic Games before the game ... In daily life, we often involve the estimation of the quality, quantity or length of such objects. Faced with the above problems, estimation is a "good prescription" when there is no need to calculate accurate results or it is temporarily impossible to obtain accurate results. Then, how to guide students to pay attention to solving such problems and cultivate primary school students' awareness of estimation? First of all, teachers should have the awareness of estimation. Secondly, teachers should consciously combine relevant teaching contents, link estimation with solving related problems in life step by step, and gradually infiltrate them so that students can deepen their understanding. For example, after learning kilograms of knowledge, students can try to estimate the quality of related items in daily life; After learning meters and centimeters, students can estimate the length, width or thickness of some objects. After knowing the number within 20, students can try to estimate how many peanuts there are in a handful ... In short, teachers should be conscientious people who inspire students to use estimates, try to combine the mathematics knowledge learned in class and find opportunities to organize students to observe and analyze; Then, through the exchange of estimation methods and skills, students can feel the fun of estimation in practical application, experience the practicality and convenience of solving problems with estimation, and highlight the application value of estimation. Second, combining with teaching, the method of infiltration estimation is combined with teaching. Although the estimate is a rough estimate, it is not a wild guess. That kind of groundless speculation is often quite different from the actual result. So how to estimate it reasonably and accurately? The cultivation of primary school students' estimation consciousness and ability is closely related to teachers' teaching. Teachers should strengthen the awareness of estimation and demonstrate the estimation method in combination with the teaching content. The teacher's estimation method is mainly reflected in the excavation of the estimation subject matter in each textbook and purposeful and systematic.

Infiltration, which needs to be interspersed in the teaching process. This requires teachers to strengthen their understanding of the importance of estimation teaching in promoting students to form a good sense of numbers and cultivate students' good sense of numbers and quantitative ability. Specifically, some estimation methods can directly or indirectly penetrate into students in their usual teaching and learning. The commonly used estimation methods are: (1) approximate estimation method. According to the actual situation, two numbers are estimated to be integer ten, integer hundred or several hundred dozens, so that we can estimate a general number or range. (2) Legal estimation method. It is to judge the result of operation by using various operation rules and properties, such as judging whether the result of 9 is. Is 4× 0. 18 = 1.692 correct? At this time, the teacher can guide students to multiply a factor (except 0) by a number less than 1, and the result is definitely less than this number, so it is easy to guess and verify the result. This estimation method is very suitable for checking whether the calculation of a problem is correct. (3) Combining with the actual estimation method. For example, the number of people and the number of car rentals must be integers, and the speed of the car is much faster than that of people. (4) rounding. For example, how many words are there in a newspaper and how many students are there in a grade ... For example, when teaching "Understanding within 10000", in order to establish the concept of 10000 for students, a large number of soybeans were prepared to deepen students' understanding of Wan through physical objects. How many soybeans are there? Students will be shocked when they first hear that 65,438+00,000 is a big number, but at this time, the problem of permeability estimation method is solved: first count 65,438+00 bags of 65,438+0000 soybeans and put them in a suitable transparent cup, which is 65,438+0000, that is. A child replied, "Fill this cup with 10 times, which is about 10000 capsules." his

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This method was unanimously recognized by the students, and soon everyone saw about 10000 soybeans ... In this experiment, those soybeans were not accurate 10000, but an estimate. According to a single quantity, the corresponding quantity is estimated. The whole experiment of rounding off zero not only makes students feel the size of 10000, but also permeates the students in the process of the experiment. For another example, with the emergence of measurement units, after learning the meters, centimeters, grams and kilograms, on the one hand, it helps students to establish the concept of corresponding teaching units, and at the same time, it allows students to contact real life and fill in the appropriate units: the blackboard is 4-, the textbook is 18-, a big herring weighs 2-, and a truck is 2-. Through these exercises, children's understanding of life experience can be deepened, and then students can make an estimate of the school. How many kilograms does the teacher weigh? Students will judge by what they have practiced, and feel much more relaxed. Third, create scenarios to enhance the awareness of estimation application. The core of students' mathematical quality is their mathematical application ability, which is mainly reflected in solving problems in life with mathematical viewpoints and knowledge. Therefore, students can be guided to consciously use mathematical methods to solve some practical problems in and out of class, and their estimation consciousness and ability can be improved. In teaching, teachers should dig deep into all the estimation resources in textbooks, closely connect with students' life experience, create realistic life scenes, carry out practical activities full of life breath, change estimation from "dispensable" to "ubiquitous", and enhance students' awareness of using estimation to solve practical problems in life independently. For example, show the students around the classrooms of the newly-built teaching building and the floor tiles to be decorated, and ask them to estimate how many floor tiles are needed to decorate the ground of the new classroom. Some students measured by hand, and some students came up with the idea of estimating how many floor tiles can be placed horizontally and vertically in the classroom. Multiply the number of tiles that can be placed horizontally and vertically to know how many tiles are needed. Some students even found that in some places when their home was decorated, the whole floor tile was still a long way from the wall, so they needed to make more preparations to make up for the vacancy, so he suggested buying more bricks to make up for it when they actually bought it. For example, before the May Day Golden Week holiday, many children have plans to travel with their families. Taking this opportunity, I designed a practical activity of "financial expert" to provide a three-day tour route from Qingdao to Rizhao, with various expenses: 238 yuan for travel agency (excluding meals), meals 1 15 yuan, and Qingdao Underwater World, a scenic spot of my choice. Kids, as far as I know,

The information provided quickly estimated that the cost of this tour was about 460 yuan. Even the children say that they should bring more money and 500 yuan when they go out ... After hearing the children's scientific and reasonable financial advice, as a teacher, I really can't look down on them, not only solving the problem reasonably through estimation, but also enriching their life experience related to mathematics and enhancing their application knowledge of estimation. Fourthly, the perception method and encouragement strategy make the perception method diversified. In teaching, teachers should teach students to use estimation.

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Strategies for solving mathematical problems with knowledge. First, let students master the strategies before the exam. Is to reasonably estimate the scope of the result of the problem. If the calculated result is beyond the estimated range, then the answer is wrong. When students encounter problems, they can actively grasp the information as a whole, quickly use intuition to make judgments and guide the direction of solving problems, so as to achieve the accuracy of the calculation results; Secondly, let students master the adjustment strategy. Due to the different methods used in estimation, the accuracy of estimation results is different, so proper use of adjustment strategy can ensure that the estimation results will be closer to the accurate value; For example, 286 3 12, some students estimate that 286 is 290, 3 12 is 3 10, and 290 3 10=600, and the result is about 600; Some students estimate that 286 is an integer of 300, 3 10, 312300 310 = 610; Different estimation strategies have different results. Thirdly, because students' life background and thinking angle are different, the methods used must be diverse. Therefore, teachers should respect students' ideas, encourage students to think independently, let students exchange and discuss, experience the diversity of problem-solving strategies in discussion and exchange, and practice the thinking method of optimizing strategies in the process of mutual evaluation and self-evaluation. In a word, teachers and students need to enhance their awareness and make joint efforts to make primary school students have preliminary estimation ability. In the process of guiding students' practice, analysis and summary, students' preliminary estimation ability is continuously improved, thus broadening students' thinking of solving related problems in life by using mathematical knowledge and mathematical thinking mode. The formation of students' estimation consciousness and ability needs long-term subtle infiltration and teachers' unremitting efforts in every class. Only in this way can students taste the sweetness of estimation, thus internalizing estimation into consciousness, and many valuable and creative estimation methods can be developed in generate. Students' estimation ability can be really improved.