As a new teacher, teaching is one of our jobs. We can record the new teaching methods we have learned in teaching reflection, so how should we write teaching reflection? The following are my thoughts on the teaching of "Decimal Multiplying Decimal" in primary school mathematics. Welcome to share.
Reflections on the teaching of "Decimal Multiplying Decimal" in primary school mathematics 1 Decimal Multiplying Decimal This section is a teaching focus of Unit 1, based on students' learning of decimal multiplying integers. Relying on students' existing knowledge and experience, we should conform to students' thinking orientation in the process of exploration, guide students to actively explore, actively think and discuss and communicate, and naturally discover the relationship between decimal places in products and decimal places in factors in the process of "questioning, exploring, dispelling doubts and using". Pay attention to the independent exploration of arithmetic and algorithm. In the whole process, I let the students make full use of the existing knowledge to explore on their own, and rely on the students' own understanding to find ways to solve new problems. Then through mutual communication, cognitive conflicts are constantly generated, and sparks of collision are generated in thinking, creating an atmosphere of continuing to explore laws and solve new problems.
(1) Try independently. When students independently calculate 4.2×3.6, they will inevitably calculate according to their previous understanding of arithmetic and logic of multiplying decimal by integer and integer by decimal. This kind of attempt can fully expose students' thinking process. I fully understand students' cognitive difficulties when calculating decimal times decimal, and find the best breakthrough point for targeted and targeted teaching.
(2) communicate your own algorithms and ideas. In the communication, I asked students of different levels to talk about their own algorithms and ideas, so as to grasp students' different thinking growth points and cognitive differences in time. For example, in the process of multiplying decimals by decimals, teachers ask students to estimate the maximum result of 2.8×3.6 first, and then ask students to calculate it again. I fully respect students and let as many students creatively participate in the exploration process of calculation. Instead of judging the correctness of students' algorithms, calculations and results, I show all kinds of different algorithms and ideas to the whole class, so that they have collisions and conflicts in their thinking and leave room for their thinking.
Solve problems with laws, so that students can further understand reasoning and obtain methods.
Using the law discovered by students to guide calculation can deepen the understanding of arithmetic, improve the perceptual knowledge of the algorithm, and lay a good foundation for summarizing the law of decimal multiplication. On the other hand, it can improve students' interest in learning and make them experience the joy of success, which conforms to students' cognitive and psychological laws. For example, in class exercises, students are first designed to practice exercises independently, then they are organized to exchange and discuss, and then they are named to talk about their ideas and algorithms in front of all the students. Through calculation and communication, students have a certain perceptual knowledge of the algorithm of multiplying decimals by decimals, and have a preliminary understanding of the law that a factor has several decimals and a product has several decimals.
Use rules, carry out special training and open training, broaden ideas and promote development.
The calculation rules of decimal multiplication have strong operability, which is the simplest summary of decimal multiplication operation, has a strong guiding role for students' calculation, and is the simplification of thinking and the optimization of problem-solving strategies. Therefore, according to the characteristics of the formula, some special exercises are designed to further strengthen the law that the decimal places of products are determined by the decimal places of factors. In order to broaden students' thinking space and imagination space, a group of open exercises are arranged to enable students to implement basic knowledge, develop their learning potential and cultivate their exploration ability. Let students feel the purpose of learning mathematics in interesting calculation, that is, apply the mathematical knowledge gained in exploration to life and work, and use mathematical knowledge to analyze and solve some life problems.
Through independent study, deskmate discussion and cooperative communication, we can discover and create decimal multiplication arithmetic and algorithm, so that students of different levels can improve on the original basis, cultivate and develop their emotions, attitudes, learning thinking ability and cooperative inquiry ability, and infiltrate mathematical thinking methods.
Reflections on the teaching of "Decimal Multiplying Decimal" in primary school mathematics II. When I took decimal multiplication yesterday, the students' vertical arrangement was very problematic. When calculating decimal multiplication, some students simply remove the decimal point and list it as an integer vertical type, and then directly use the changing law of the product to point a few decimal points on the horizontal type. Some students, influenced by decimal addition and subtraction, like to align the decimal point instead of the end. But their answer is also correct. According to the requirements of the textbook, decimal multiplication should be calculated by integer multiplication first, and the natural vertical should be aligned at the end like the vertical of integer multiplication. I once read an article in the magazine "Mathematics Teaching in Primary Schools", which said: In vertical multiplication with multiple digits, it is reasonable for some students to multiply each digit of the above factor by the digits of the following factor respectively. Then I wondered if fractional multiplication allowed him to write like this. The vertical type was originally designed for the convenience of calculation. The student thinks that the decimal point is aligned and looks neat and clear, so why does he have to write vertical alignment as the final alignment?
I posted this post on the primary school mathematics teaching forum yesterday. The host said: I don't think so. You can't say why not. Although I still don't understand, I still try my best to make students write vertically.
Today, I asked some students who want to make mistakes no matter how they teach, and asked them to write more numbers and less numbers on it, so that the vertical z is correct and the calculation accuracy is improved.
Reflections on Decimal Multiplying Decimal Teaching in Primary Mathematics 3 Decimal Multiplying Decimal is the content of Unit 1 in the first volume of Grade Five. The teaching focus of this content is the calculation rules of decimal multiplication; The difficulty in teaching is the location of decimal places and decimal points in decimal multiplication. If the number of decimal places of the product is not enough, it should be preceded by 0.
Decimal multiplication by decimal is taught on the basis of students' learning decimal multiplication by integer. I think students have a certain foundation in this knowledge point. As long as they master the arithmetic of fractional multiplication, it should be easier to learn, but the facts are not satisfactory. In after-class exercises, students make many mistakes: 1, and the method is wrong: for example, in teaching example 3(2.4×0.8), students can fluently say that the product multiplied by two factors will be expanded by 10 times, and in order to keep the product unchanged, the product will be reduced by 65438 times. But in the process of calculation, some students can't combine arithmetic with method, and can't solve the decimal point problem of product correctly. Some students confuse decimal multiplication with decimal addition, or just look at the decimal places of a factor. 2. Problems about 0 in calculation; Some students have zero at the end of the product, so cross it out first and then point the decimal point; Some students with learning difficulties have to multiply by 0 again when the factor is a pure decimal or there is 0 in the middle of the factor. 3. Calculation error: When there are many digits in the factor, individual students directly write the numbers (for example, 4.5 15 is directly in the vertical form of 2. 1 without calculation process), and then complete the vertical form without writing the numbers in the horizontal form.
Faced with the mistakes made by students, I have to re-examine my classroom and my students, and I deeply reflect on this: this unit is not as simple as I thought, not only should we pay attention to the connection between old and new knowledge, but also highlight the changing law of product, vertical writing format and the relationship between decimal places in factors and decimal places in products. To this end, I decided to improve from the following aspects:
1. Analyzing and judging students' mistakes as teaching resources, the effect of correcting mistakes is better than that of correcting books by students.
2. Vertical thinning of columns. Key points: ① "last bit alignment" when decimal multiplication column is vertical. (2) After calculating the product, count two factors * * * with several decimal places, and count the same decimal places from the right to the left of the product. (3) Calculate the result by counting the decimal point first, and then cross out the 0 at the end of the product.
3. We should strengthen the comparative practice of decimal addition and subtraction and decimal multiplication.
Reflections on the teaching of "Decimal Multiplying Decimal" in primary school mathematics. This lesson is the first time for students to contact decimal multiplication. I think we should pay attention to the following points in teaching:
1. Let students discover the rules by themselves. Mathematics teaching should be people-oriented; Mathematical problems should come from life and then be applied to life; When teaching, we should consciously carry out inquiry teaching. Teachers should return the initiative of learning to students, and let go when it is time to let go. When students can take the lead as the masters of the classroom, they should actively interpret the classroom with their own rationality and clarify their unique views, thus adding color to the classroom. We should let go and enjoy their performances to the fullest.
2. Highlight the change of decimal number. The change of decimal places is the difficulty of this lesson, so I advanced the teaching content to Example 2 and arranged two exercises, one is to explore the relationship between the decimal places of products and the decimal places of factors, and the other is to judge the decimal places. After judging the decimal places, students choose two questions to calculate and realize that the decimal places that are not products are the same as the decimal places of factors.
3. Highlight the vertical writing format. With the previous understanding of arithmetic, students no longer find it difficult to calculate 0.8×3 vertically. Finally, they guide the summary: decimal times integer should be aligned at the end.
However, there are also many shortcomings. I need to improve my adaptability in classroom teaching. Sometimes I ignore students' ideas, fail to capture valuable teaching resources in students' speeches in time, and teaching does not continue in a dynamic way. This shows that teachers should pay attention to listening and thinking in class, and I will pay more attention to these details in future teaching.
Reflections on the teaching of "Decimal Multiplying Decimal" in primary school mathematics;
1. Can students understand why 1008 is divided by 100 in the example?
2. Can students find that the decimal places of the product are the sum of the decimal places of the factors?
3. Will the new lessons in the afternoon be worse than those in the morning? Will the students have a problem with it?
For example, ask a question, formulate it and estimate it. After putting forward the vertical calculation, the students immersed themselves in the calculation and toured around by themselves. Some students don't know how to calculate, so they gently remind them to calculate the formula into an integer. Some students face 1008. Although they put the decimal point between two zeros, they don't know why they are here. Tell me the estimated results; Most students know that because both factors are multiplied by 10, the product is multiplied by 100. To keep the original product unchanged, you need to divide the current product by 100. When several students talked about the whole calculation process, other students suddenly said, "Oh! I see! " So everything is connected. Try it. No problem. Let the students sum up the calculation rules themselves. Because in the teaching of multiplying decimal by integer, we attach great importance to let students summarize the calculation rules of multiplying decimal by integer, so here we only need to add "one * * *" to "how many decimal places are there in the factor". Finally, there are only five words on the blackboard: "calculate, look, count, point and correct". Remind students that they can check the calculation by estimating.
Today's example 2 still uses the example of the second class in the afternoon to talk about relevant mathematical information. After asking the first question, the students do their own vertical calculations. I don't need to explain at all, so I can say that when the decimal places of the product are not enough, we should use 0 to make up for it. The following "try it" is naturally smooth sailing.
Judging from the two-day homework, students' mistakes are not in methods, but in calculation, not carrying, misreading numbers, 7 × 7 = 46 and so on. Therefore, this part of my own judgment is "finished!" Example 3 will be given next Monday.
Having nothing to do after class, I wrote Reflection on Teaching. The feeling is: "this part of knowledge is taught on the basis that students have mastered the calculation method of multiplying decimal by integer and the change of decimal size caused by moving decimal places." Although initially worried that students don't understand that the decimal places of the product are the sum of the decimal places of the factors. However, when I was teaching decimal multiplication, I paid great attention to let students sort out the calculation rules through calculation, so I found the attention points (simplify what can be simplified, and use 0 to make up when the decimal places of the product are not enough) and check the calculation through estimation. Therefore, in this part of the teaching, I can easily complete the teaching task.
Through the smooth teaching of these two examples, remind yourself to pay attention to the following points in teaching:
1. For the knowledge teaching of each unit, we must explain it in a down-to-earth manner, pay attention to the cultivation of students' ability, pay attention to the training of double basics, and let students pass every knowledge point. Don't stir-fry uncooked rice, so that your later teaching can proceed smoothly.
2. Students have different academic feelings, different acceptance abilities and different foundations. We should try to seize forty minutes in class and pay more attention to the knowledge of underachievers. Give them more opportunities to speak and act.
3. Pay attention to delving into the teaching materials before class, pay attention to the connection between the content to be taught and the teaching content in the early and late stages, clearly understand the students' learning situation, preset the places where students may have doubts, and improvise the problems existing in students. "
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