Second, say the goal.
According to the characteristics of the textbook, I will talk about the teaching objectives of this lesson from three aspects: knowledge, skills and emotion:
1. Students can estimate multiplication in the process of active participation and cooperative learning, and can explain the idea of estimation.
2, can use the knowledge of multiplication estimation to solve some specific problems in daily life.
3. Create a space for students to actively explore and estimate knowledge, cultivate estimation consciousness and improve estimation ability.
4. Students realize the necessity of estimation and enhance their confidence in learning estimation well. Teaching emphasis: make students master the estimation method of multiplying two digits by two digits.
Teaching difficulties:
Flexible use of multiplication estimation to solve specific problems in real life. (Interlanguage: How to guide students' learning with vivid and clear teaching methods is the most important thing. This involves how teachers teach and how students learn. Teaching methods and learning methods complement each other and are inseparable. )
Three. Oral English teaching methods and learning methods
Teaching methods:
It is pointed out in the curriculum standard that the thinking of students in the first phase is mainly in images, and materials that conform to children's psychological characteristics should be selected. For example, choosing life scenes that students are familiar with, and choosing vivid and interesting material content, I believe it can attract students' attention and stimulate students' interest. At the same time, it is necessary to create a situation in which estimation methods are used to solve practical problems, so that students have the opportunity to understand the meaning and form of estimation and master estimation skills. In teaching, students should be encouraged to explore and try different estimation methods and cultivate their ability to use different calculation strategies flexibly to solve problems. In the teaching process, teachers should actively guide students, encourage students to explore thinking and stimulate their enthusiasm for learning.
Studying law:
In a relaxed and open classroom atmosphere, students actively participate in the problem situations created, independently explore their own estimation methods, carry out cooperative learning and communication among team members, realize the collision of wisdom, experience the joy of success, and let students learn different estimation methods through thinking and inquiry, and make progress through independent exploration, independent thinking, cooperative learning and mutual communication. Teachers' "teaching" should be: creating situations, stimulating interest, encouraging exploration and guiding discovery; Students' "learning" can be achieved: courage to try, independent exploration, cooperation and exchange, and common development.
Fourth, talk about the teaching process
(1) Stimulating interest into pedagogy and psychology research shows that when learning materials are related to students' existing knowledge and life experience, students will have interest in learning. Therefore, before exploring new knowledge, this class created a situation of shopping in the supermarket. Students, we will hold a get-together in the afternoon, and we will buy a lot of fruits. Let's go shopping in the supermarket! Today's special: grapefruit per 3 yuan. I want to buy 2 1. How much is it? This is the estimation method of multiplying two digits by two digits that students have learned in the past, and the two digits are estimated as integer ten digits. This link not only allows students to review the knowledge points of multiplying two digits by one digit, but also lays a good foundation for new knowledge. It also allows students to enthusiastically participate in the situation created by teachers and actively participate in problem solving, thus making a logical transition to the exploration of new knowledge. If there are 350 students attending the get-together, can this small auditorium sit down? In real life, we don't need its actual data for a problem like this. We can calculate its approximate data by estimation. Now let's estimate whether 350 students can sit down. This makes students feel the necessity of learning two-digit multiplication estimation.
(2) Exploring New Knowledge Mr. Ye Shengtao said: "Being a teacher is like helping children walk. Give him a hand and get ready to let go. If you can put it down, put it down. " Therefore, I only inspire and guide the key points in teaching, leaving enough time and space for students. Students all have the experience of estimating two digits with one digit. They will estimate two digits into an integer. I don't think it is a problem for students to learn the estimation of double digits through double digits. I use the teaching method of knowledge transfer to let students explore and understand the method of multiplication estimation through active participation.
1, think independently, think about how you would estimate?
2. Then the groups exchange their own evaluation strategies. Professor Zheng Yuxin once said: "A hasty discussion without personal reflection, such as passive water, expresses neither mature nor profound views, let alone individuality and originality." Our classroom needs meditation, superficial excitement will only cover up students' thinking, and students will only have the desire to communicate if they think for themselves. Therefore, cooperation and communication must be based on independent thinking.
3. Ask students to report the estimation method and guide them to say their estimation ideas. (Show the algorithm and summarize the estimation method. ) I guess students will have several estimation methods: treat two factors as integer ten close to them, and then determine the range of their products by oral calculation. ① 18×22≈400 (a) 20 20 Take one of the factors as an integer close to them, and then determine the range of their products by oral calculation. ② 18×22≈440 (pieces) 20 ③ 18×22≈360 (pieces) 20 When students express their estimation ideas, teachers can give them timely and appropriate appreciation. At the same time, teachers are not eager to evaluate various estimation methods, but actively guide students to adopt various algorithms. In an interview with Professor Liu Jian, there is a saying: When teachers advocate the diversity of algorithms, should they propose new solutions? The so-called method should combine students' personality, and there is no method suitable for all students. Every student's way of learning and thinking is unique. We should respect students' own choices, and we can't stipulate the so-called methods that all students must adopt according to the thinking standards of one or a group of students. Therefore, in teaching, I guide students like this: Which method do you prefer? Tell me why you like it. This not only respects students' individual thinking methods, but also cultivates students' individual development. After exploring new knowledge, I arrange exercises at different levels, so that students can consolidate estimation methods, cultivate estimation consciousness and enhance estimation confidence.
(3), consolidate and improve
1, basic exercise "
Practice after learning new knowledge is the main link for students to internalize knowledge, and it is also the link for students to consolidate estimation methods. Show the textbook page 59 "Do". A. Look at the picture and do it independently, and choose your favorite estimation method. B, please talk to your deskmate about the estimation strategy after completion. Let students feedback new knowledge in time and consolidate the estimation method.
2, improve the practice
If you leave the colorful background materials, learning will become "passive water, trees without roots". Therefore, after the basic exercise, I set the improvement exercise in the situation. Let students use multiplication estimation flexibly in specific life situations to improve their estimation ability. (Textbook page 665438 +0, questions 7 and 8) Bring students into the zoo with vivid pictures of the zoo, choose their favorite animals for estimation, and then introduce them in groups. In this exercise, students may encounter such a difficulty: "1 minute" is inconsistent with the name of the given unit, so the teacher should remind students in time at this key point. The exercises in question 8 go deeper than those in question 7. Ask students to look for mathematical information in pictures instead of enumerating the mathematical information in the text. Cultivate students' ability to collect mathematical information and further improve their ability to solve practical problems. It is children's nature to love to play, and setting up the "play" link is based on children's characteristics and teaching purposes. Students express themselves in game competitions, play in middle schools and schools, and improve their estimation ability at the same time. Probably a race to answer questions. In groups. If you answer a question correctly, you will get an apple. If you answer a wrong question, you will get an apple. Through games, students' thinking agility will be cultivated. Through practice in games, students will participate in activities with passion, and their estimation ability will be improved again.
3. Open practice
Open-ended questions are conducive to developing students' divergent thinking and creative thinking, giving students a broader space to show their abilities and take care of every student in the class. Multiplication estimation is often used in real life, and ah! It is estimated that the world is also colorful. Now, please use what you have learned today to make up an application problem of multiplication estimation. This design makes students feel that "although the class is tired, the meaning is still unfinished." It helps students to keep their interest, enhance their awareness of estimation, and feel that multiplication estimation is everywhere in life. Let students at different levels get different development.
(4) Self-evaluation
Do you like this course? What did you get? Let students participate in the summary, which is not only convenient for students to understand the mastery of new knowledge, but also enables students to learn self-evaluation and enjoy the joy of success.
(5) Transfer
Please write an article about math diary related to multiplication estimation.
summary
This lesson creates scenarios to make students fully understand the significance of estimation, master various methods of multiplication estimation, solve practical problems and make students like estimation. Develop the flexibility and creativity of students' thinking in the process of cultivating their estimation ability. Make students fully gain successful experience, have high interest in learning, actively participate in exploration, and achieve common development in cooperation and exchange. Classroom is like a vast sky, in which every student can appreciate the infinite mystery of multiplication estimation.