First, the teaching requirements of the curriculum standard for "two digits multiplied by two digits".
? The Mathematics Curriculum Standard for Compulsory Education (version 20 1 1) puts forward that "you can calculate the multiplication of two digits", "you can know parentheses, and you can perform simple integer elementary arithmetic (two steps)", "you can choose a suitable unit to make simple estimation according to the specific situation, and experience the function of estimation in life" and "you can experience the process of communicating with others about their respective algorithms". It can be seen that the curriculum standard puts forward clear requirements for the teaching of "double digits multiplied by two digits" in terms of knowledge and skills, problem solving and so on. In particular, it emphasizes the importance of estimation and problem-solving teaching, aiming at making students feel the significance and value of estimation, developing their sense of numbers and improving their problem-solving ability.
? Second, the arrangement of the content of "double digits multiplied by double digits" in the textbook of Beijing Normal University Edition.
? Beijing Normal University Edition has not specially arranged this part of the content, but from three aspects: unit structure setting, content knowledge point arrangement and examples, it shows a spiral upward trend.
? 1. Company structure setting.
? "Multiplying two digits by two digits" is the teaching content in Unit 3 "Multiplication" in the second volume of the third grade of primary school. This unit is the teaching content set on the basis that students can skillfully multiply a number by an integer of ten and a number by a pen, and it is also the basis for learning "three digits by two digits" in the future. The curriculum arrangement of "playing games to learn mathematics" is also a transition from table multiplication to multi-digit multiplication by one digit and then to double-digit multiplication by two digits.
? 2. Arrangement of content knowledge points.
? In "Two Numbers Multiplying Two Numbers" published by Beijing Normal University, it is arranged as follows: find a rule (two digits multiplied by integer ten, dozens of oral calculations), queue up for performance (multiplication without carry pen), and make a movie (multiplication with carry pen). Emphasis is placed on the interpretation of basic arithmetic algorithms.
? 3. Arrangement of examples.
? The layout features of the "two-by-two" unit in Beijing Normal University Edition are as follows.
There are no scenes and illustrations in oral calculation, and the instructions are in the form of question strings and dialog boxes. Heuristic method is mainly about thinking about related problems, and there are two ways to solve problems, without cooperative tips. Written calculation can be divided into no carry and carry, no illustrations but life scenes. Drawing, question string and dialog box are the main teaching methods, and there are relatively more inspiring methods and ideas, and the matching tips are correspondingly richer.
? The textbook of Beijing Normal University pays attention to the use of question strings, so that students can gradually explore and apply new knowledge in questions, thus mastering new knowledge. Beijing Normal University Edition pays more attention to the diversity of algorithms to meet the learning needs of different students.
? Third, the understanding of teaching "two digits multiplied by two digits".
? 1. Integrate the knowledge structure.
? (1) The choice of knowledge points directly affects teachers' teaching and students' learning. Therefore, when preparing lessons, teachers must have a deep understanding of the textbook "Double Numbers by Double Numbers". According to the logical structure of knowledge and students' cognitive structure, combined with their own teaching experience, select and integrate knowledge points and improve teaching design.
? (2) Pay attention to the process of knowledge formation.
The teaching of "two-digit times two-digit" should not only guide students to explore calculation methods in combination with the actual situation, but also guide students to compare various methods in the actual situation and then summarize the calculation rules, gain basic experience in exploring mathematical problems, and make the classroom reflect "mathematical taste".
? 2. Pay attention to the application of intuitive model.
? The algorithm of "two-digit times two-digit" is more specific, which is based on arithmetic theory and gradually generalized and abstracted, so teachers should pay attention to the use of intuitive models in the teaching process. Such as: bitmap.
? 3. Pay attention to inspiring examples.
? Teaching in the form of questions can stimulate students' enthusiasm and initiative in learning, and enlightening questions can make students think positively, produce new ideas and concepts, and carry out creative learning activities.
? 4. Guide students to carry out group cooperative learning.
? Cooperative learning is good for students to communicate and solve problems. Students experience the same problem and different thinking collisions. It can not only improve and develop the cognitive structure, but also help to improve students' cooperative consciousness and ability.