The teaching content of this lesson is the first lesson of Unit 6 in the first volume of the third grade-the pen multiplication of multiple digits multiplied by one digit does not carry. The position of this part in the textbook is:

In one unit, students have learned to master the oral calculation of integer ten, integer hundred, integer thousand multiplied by one digit and the estimation of multiple digits multiplied by one digit. Later, they have to learn the carry-write multiplication of multiple digits multiplied by one digit, which includes several parts in turn: one-time carry, continuous carry, multiplication with zero in the middle and zero at last. One of the teaching tasks is to help students learn to choose suitable methods for flexible calculation according to specific problem situations, so that students can establish judgment and selection algorithms.

In multiplication: The study of this course is based on the students' understanding of multiplication and its meaning, the mastery of table multiplication, the correct calculation of multiplying integer ten, integer hundred and integer thousand by one digit, and the estimation of multiplying multiple digits by one digit. At the same time, it lays a foundation for continuing to learn the trial quotient, multi-digit multiplication, two-digit division and decimal multiplication and division of multiple digits. For example, the vertical forms of integer multiplication and decimal multiplication are all aligned on the surface, and the calculation methods are basically the same. For another example, in the teaching of integer multiplication, only one-digit multiplication and two-digit multiplication are involved, and only related exercises appear in the textbook, but in some problems, three-digit multiplication or even four-digit multiplication will also appear. If students don't have the ability to transfer methods, the calculation accuracy will obviously not reach a higher standard. In addition, one of the fundamental reasons for the low accuracy of students' writing carry multiplication (especially multi-digit carry multiplication) is the low accuracy of students' oral multiplication and addition based on table multiplication.

In the four operations, the calculation method of pen multiplication and division is similar to that of pen addition and subtraction of two or three digits. For example, first determine the vertical writing format (mostly aligned with the same number of digits), and now determine the operation order (mostly starting from single digits or low digits, and pen-based division starting from the main theme), then calculate the positioning step by step, and finally form the operation result. Therefore, we should pay attention to the communication of methods in teaching and cultivate students' ability to draw inferences from others and transfer methods. A careful study of the methods of Example 1 on page 74 and Example 2 on page 76 in the first volume of Grade Three shows that one of the similarities is the connection between written addition and written multiplication.

Second, the analysis of learning situation

Multiplying multiple digits by one digit (no carry), most students can do oral calculation correctly, and some students have mastered the method of written calculation. Before class, I made a survey in my class. The content is as follows:

1. Write the number directly.

14×2= 23×3= 12×4= 134×2=

2. Write down your own ideas when calculating 134×2=, and then list the vertical calculation of 134×2= vertically.

The findings are as follows:

Question 1: Of the 43 students, 33 got all the answers correctly, and 8 got only the wrong answers. 1 got the wrong answers twice.1The students didn't finish because of their usual slow speed.

Question 2: Among 43 students, 42 students can correctly express their own calculation process, and 16 students can calculate vertically.

According to the students' previous mathematics learning experience and the age characteristics of the third grade students, the students are analyzed in combination with the above questionnaire. It is found that most students can convert multiplication without carry into addition for calculation, and some students have learned vertical writing from their parents or teachers in off-campus classes.

In computing teaching, we should not only pay attention to the teaching content, but also pay attention to students' existing knowledge, experience, ability and development needs. We should not calculate for the sake of calculation, but method for the sake of method. On the contrary, we should redefine the teaching objectives and difficulties on the basis of a comprehensive analysis of the teaching content and students' situation. For example, in this class, it is obvious that students can do oral calculations quickly and correctly. Why do they have to learn written calculation methods? Isn't that unnecessary? Students are in such a state of learning for the sake of integrity and integrity, and learning for the sake of learning. How can they become interested in mathematical inquiry? If you don't care about students' actual situation, teach them how to set up teaching materials, so that the teaching of calculation becomes a simple exercise and our students become calculation machines.

When determining the teaching objectives of each class, we should consider one point, that is, how to learn from this class and let every student have new gains. In other words, apart from "knowledge and skills", what aspects or aspects have students improved?

Third, teaching objectives and difficulties

In fact, as the first lesson of written multiplication, this course should first undertake the following teaching tasks:

1. Guide students to perceive the important position of this section in the whole unit and even in the calculation teaching of primary schools, and to perceive the connection with related content in skills and methods.

2. Guide students to explore the calculation method of pen multiplication, understand arithmetic, and use this skill to correctly calculate the multiplication of multiple digits multiplied by one digit without carrying.

3. Perceive the application scope and value of pen multiplication in the exploration, and cultivate students' consciousness of choosing the appropriate algorithm for flexible calculation according to the actual situation.

4. Initially cultivate students' calculation habit of "estimate first, then calculate and then compare".

[Thinking: Whether there are too many teaching objectives above will lead to the consequences of "biting off more than one can chew", which will eventually lead to the phenomenon that key objectives cannot be completed. ]

Emphasis: Guide students to explore the calculation method of pen multiplication, understand arithmetic, and use this skill to correctly calculate the multiplication of multiple digits by one digit without carrying.

Difficulties: Cultivate students' calculation habit of "estimating first, then calculating and then comparing".