This unit is based on integer multiplication, the meaning and nature of fractions, and it is also an important basis for learning fractional division and percentage. The textbook embodies the requirement of understanding the meaning of calculation in combination with specific situations, and understands the meaning of calculation by solving practical problems and combining the calculation process. This lesson is the second level of 1 fractional multiplication teaching. Learning fractional multiplication requires students to understand and learn through operation on the basis of understanding the significance of fractional multiplication.

Analysis of learning situation:

It is not difficult for students to remember the calculation method of multiplying the score by the score. However, it is difficult to understand the arithmetic of fractional multiplication. In addition, students are easy to confuse the calculation of fractional addition and fractional multiplication, and they should help distinguish them through various exercises.

Teaching objectives:

1. Make students understand the operation of fractional multiplication through operation activities, so as to master the calculation method.

2. Cultivate students' hands-on operation ability and observation and reasoning ability.

3. Develop a good study habit of careful calculation and standardized writing.

Teaching emphasis and difficulty: understand the calculation of fractional multiplication and master the calculation method.

Teaching philosophy:

When designing teaching, I mainly consider the following aspects:

1. Create realistic situations and ask mathematical questions, so that students can learn calculation in realistic situations and realize that calculation is the need to solve practical problems.

2. Change students' learning style, and learn fractional multiplication through hands-on, independent exploration and cooperation.

Teaching process:

First, create situations and introduce new lessons.

1. Teacher: Recently, Mr. Hu's family was decorating the house (showing pictures of painting the wall) and asked such a question: How many points can the decorator paint this wall in an hour?

2. Student solution: 1/5×4=4/5 Q: Why use multiplication?

Just now, we have solved the problem of how much to paint in four hours. How many walls can we paint in1/four hours?

How to form? Why do you count like this?

4. How to calculate 1/5× 1/4? This is the "score by score" that we are going to learn today. (blackboard writing topic)

Second, begin to operate and explore arithmetic.

1. Teacher: Let's discuss how to multiply the score by the score. Take out the prepared rectangular paper and use it to represent this wall. Draw the area of 1 hour first, and draw a score of this paper.

Students do it by hand and how to communicate.

2. Teacher: Draw this wall with a score of 1/4 hours, that is, with a score of 1/5. Discuss in groups. How to draw 1/4 of 1/5?

Group Report: Divide the painted part of 1/5 into 4 parts and paint out 1 part.

3. Teacher: It can be seen from the test paper that 1/4 1/5 accounts for how much of this test paper? ( 1/20)

We can get1/5×1/4 =1/20. According to the coloring process, can you tell me how it was obtained?

4. Students discuss the exchange report, and the teacher summarizes: First, divide this paper into five parts, 1 is 1/5 of this paper, and then divide this paper into four parts, that is, divide this paper into 5×4=20 parts, and 1 is 65438 of this paper. So1/5×1/4 =/kloc-0 /×1/5× 4 =1/20 (blackboard writing).

Thirdly, migration and extension, and induction of laws.

1. Ask such a question: How many parts of this wall was completed in 3/4 hours?

Teacher: How to arrange it? What does 1/5×3/4 mean? What is 3/4+0/5 of 65438? ) Can you color 3/4+0/5 of 65438?

2. Students begin to operate and exchange calculation methods and ideas: As before, this paper is divided into 5×4=20 copies, but the difference is that you can get1/5× 3/4 =/kloc-0 /× 3/5× 4 = 3/20 (blackboard writing).

3. think about it: how to calculate the score multiplied by the score?

Student summary: the score multiplied by the score should be the numerator multiplied by the numerator and the denominator multiplied by the denominator.

Fourth, consolidate practice and deepen improvement.

Teacher: Do you know what the smallest bird in the world is? Introduce the related knowledge of hummingbirds and give 4 examples.

2. How to form it? According to what formula?

3. Let the students calculate independently and then feed back the calculation process, emphasizing the subtraction before multiplication, which can make the calculation simple. The emphasis is on the restored writing format.

4. Class summary: What did we learn today? How to multiply the score by the score? How to divide a fraction by an integer?

5. Students finish "doing one thing" independently.