Recently, the author participated in the evaluation activity of excellent mathematics courses organized by the county experimental primary school, and listened to the same class of three teachers-"Two-digit Multiplying Two-digit Oral Calculation" (the sixth volume of People's Education Edition), which was quite touching. The evaluation adopts the way that the teacher prepares lessons regularly after drawing lots, and then borrows lessons to attend classes. By creating a shopping teaching scene, the three teachers led the students to ask a series of questions, asked them to list the formula of 30× 10, and then asked them to optimize the algorithm in the comparison algorithm. Finally, they asked students to use "3× 1=3, and then 30× 10=300" to reason and complete the teaching task.
During the lecture, two students in two classes asked the teacher this question: "Teacher, why is 30× 10=300?" The teacher thought for a moment and explained that because 30× 1=30, it is 30× 10=300 (that is, 1 30 is 30 and 10 30 is 300). The student didn't seem to understand the teacher's explanation and sat down with a puzzled face. We also feel that the teacher's explanation seems to be explaining an algorithm, rather than explaining arithmetic from the original cognitive level of students.
This kind of mathematics teaching is often a difficult point in teaching, and teachers should seriously consider it when preparing lessons. How to effectively face students' questions in teaching.
Understand students' questions and encourage them to ask questions.
Understanding the meaning of a problem is the premise of solving it. Some teachers don't understand students' questions in teaching and take an indifferent attitude towards students' questions, which can easily hurt students' learning initiative and enthusiasm, leading to students' reluctance to ask questions in the future. In the last exercise of this class, a student asked such a question: "Teacher, why is 50×40=2000, and there are three zeros behind the calculation result?" Because the teacher understands that this question is a refutation of 30× 10=300, let the students say the order of oral calculation: calculate 5×4=20 first, then 50× 40 = 2000 (the two numbers after 20 are marked with red chalk). So students can understand why the result is three zeros instead of two zeros. In short, teachers should give students more time to think and encourage them to question and ask difficult questions. As long as the problem revolves around the theme of the class, the teacher should first praise and encourage. You know, students' thirst for knowledge is constantly generated with the encouragement of teachers' praise.
Teachers should follow students' cognitive level when dealing with difficult problems.
"Why is 30× 10=300?" This is a math teaching problem. Students' original cognitive level is that they have learned the oral calculation of multiplying two digits by one digit, such as 10×9, 30×9. Therefore, when reviewing the introduction, teachers should start with solving these problems, and let students get the formulas: 10× 10 and 30× 10 through variants, thus revealing the topic-two-digit multiplication by two-digit oral calculation, and then guiding students to solve this problem. When students have a certain cognitive preparation for 30× 10=300, they will think of using the existing knowledge and methods to understand this new knowledge, and they will say: because 30×9=270, and 30× 10 can be expressed as 9 30s plus130s, which is 270 plus. This teaching strategy fully considers the students' existing cognitive level and solves the arithmetic problem by "bringing forth the old and bringing forth the new". Unfortunately, many of our teachers have forgotten this traditional teaching strategy, so that they can't answer students' questions correctly.
Teachers can't answer questions, but they should solve them with the help of students' thinking.
If the teacher can't answer the above questions at the moment, let the class think about how to explain the problem. We find that when teachers encourage students to diversify their algorithms, many students think that "30× 10" can also be used as "30× 5+30× 5 = 300", which is also an algorithm to explain arithmetic. Students' thinking in teaching is often unexpected and can effectively solve problems. Teachers should establish the concept that teaching is equal and students are individuals with individuality and creativity. Teachers should trust students, make full use of their existing cognitive level and guide them to acquire new knowledge independently. In this way, the active, exploratory and cooperative learning methods advocated by the new curriculum can be effectively applied in teaching. Teaching and learning from each other is an eternal teaching principle, and the teacher who learns to learn from students is the teacher that students like.
For problems that teachers and students can't solve, teachers should ask experts for help after class.
A teacher is by no means a good teacher when dealing with the problems raised by students. The current curriculum reform has put forward many effective suggestions for teachers' professional development. Teachers' practical reflection and professional guidance are important ways for teachers' professional development. The growth of many excellent teachers also shows the significance of constantly reflecting on teaching practice to promote teachers' professional growth. It is not terrible for teachers to encounter difficulties and setbacks in teaching. What is terrible is that the teachers adopt an evasive and careless attitude. For example, in this class, two teachers think that their algorithm explanation is correct after class. Stubborn opinions often mislead others' children. It is a valuable quality of many excellent teachers to dare to face up to teaching problems and conduct in-depth research.
Teaching should create expanding questions and encourage students to explore boldly.
When the teaching of this class entered the final stage, a teacher asked the students to calculate a question orally, "340×50=?" Many students can't figure it out At this time, the teacher guides the students to calculate 34×5 first, and then add two zeros after the number. The students are very active and interested in learning. Finally, the teacher stressed that we must learn the complex oral calculation method of multiplying two digits by one digit in the future, and this method is also an important operation skill that we often use in our in-depth study in the future. Appropriate infiltration of new content to be learned in the future is conducive to encouraging students to explore boldly and is a good teaching strategy for new curriculum teaching. In short, in the teaching process, creating expanding teaching questions for students is conducive to stimulating students' interest in learning and developing their thinking ability.
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