Analysis of academic situation: Grade five students have certain abilities of operation, observation, induction and generalization. With the previous learning foundation of fractional multiplication and reciprocal, it is not difficult for students to summarize the calculation method of fractional division by integer through the activities of drawing, calculating, thinking and filling.
Analysis of teaching content: Fractional division (1) is the content of the first lesson of Unit 5 of Beijing Normal University Edition. It is taught on the basis of students' learning fractional multiplication and understanding reciprocal. There are two problems in the textbook, that is, dividing 4/7 into 2 and 3 parts on average, so that students can solve the fractional division with the help of graphic language in the process of daubing and calculating.
Teaching objectives:
1. Explore and understand the significance of fractional division in activities such as painting and calculation.
2. Guide students to explore and master the calculation method of fractional divisibility and calculate it correctly.
3. Be able to divide fractions by integers to solve simple practical problems.
Teaching emphasis: guide students to explore and master the calculation method of fractional divisibility and calculate it correctly.
Teaching difficulties:
1, explore the calculation method of dividing a fraction by an integer.
2. Be able to divide fractions by integers to solve simple practical problems. Teaching aid preparation: rectangular paper, onion mathematics micro-class.
Instructional design:
First, create a situation to ask questions.
1. Question: Please divide 4/7 of the rectangular paper you prepared into two parts. How much is each part of this paper?
Teacher: Please think about how to solve this problem. (ppt shows self-study skills)
(1) Use the study paper in your hand, draw it and work it out, and try to solve this problem.
(2) Talk about each other's ideas at the same table.
(3) Please take out what you have drawn.
Communication: Why do you want to draw it like this? How much is this newspaper? Are there any different painting methods?
(4) Reporting Communication When reporting feedback, it shows students' discredited and differentiated thinking.
Through thinking and operation, students can achieve * * * knowledge;
Idea 1: 4/7 has four 1/7, which is divided into two parts on average, and each part is two 1/7, which is 2/7.
Idea 2: Divide this paper into 7 parts, take 4 parts, and then divide these 4 parts into 2 parts, which is exactly 2/7. List the formula 4/7÷2=4÷2/7=2/7.
Idea 3: Divide 4/7 into 2 parts on average, that is, what is 0/2 of 65438+4/7? It can be multiplied by 4/7÷2=4/7× 1/2. This is the fractional division that we will learn in this lesson. (blackboard writing topic)
Design intention: Through painting activities, guide students to list division formulas, and let students feel the significance of fractional division.
Teacher: We found our own solution through hands-on operation. Next, let's see what problems they have encountered in the world of fractional division. (Play onion video micro lesson)
How do they distribute energy packages? How to divide it among three people?
2. Explore again with the help of graphics.
? After watching their performance in the escape game of fractional division world,
Please complete the following questions.
Question: Divide 4/7 of a piece of paper into 3 parts. How much is each part of this paper? Please paint it.
Communication: (Show students different painting methods) Students divide four-sevenths of rectangular paper into three parts, and then color one of them. Who can list a formula according to this process? How can we work out this figure?
(Teacher asks: Why do you use × 1/3 for calculation? ) What is the relationship between observation 3 and 1/3? If you divide by 3 and multiply by 3, can you divide by an integer and multiply by its reciprocal? Let's verify it. (The teacher shows three sets of formulas)
1/3÷5 4/5÷3 ? 1/3÷5 refers to oral calculation.
Ask the students to observe each group of formulas and tell their findings. According to these three formulas and the last question, how do you think the score is calculated by dividing it by an integer? (After the students dictate the algorithm)
Design intention: the calculation method of dividing the score by integer is the focus and difficulty of this course. In order to let students master this part of knowledge better, I will let students further perceive the meaning of fractional divisor through painting, initially perceive the calculation method of fractional divisor divided by integer, and then ask whether it can be multiplied by the reciprocal of integer divisor. Through three sets of formulas to verify the hypothesis, let students experience the whole process of knowledge formation and break through the teaching difficulties under the guidance of teachers and combined with onion mathematics micro-course.
Fourth, practical application.
1, calculating
8/9÷6 12/ 15÷4
Let the students observe without a chart, and then let them talk about their own ideas. Finally, you can draw a point and one to prove the conclusion. )
Step 2 fill it in
Teacher: When you learn knowledge, you should use it flexibly. Please fill in the numbers in the red box of the second question on page 56 of the textbook. The students are independent in the red part of the second question on page 56. Collective revision.
Step 3 solve the problem.
Teacher: In order to make our campus cleaner, the school divided our class into health areas. This week, it's the first group's turn to be in charge of sanitation in the health area. The teacher wants three-quarters of the health area to be divided equally among four people. Can you figure out how many parts of the whole health area each person is responsible for? Students answer the above questions in their exercise books. Refers to the completion of the student report.
Many problems in life can be solved by fractional division. Who can talk about the problems in life like a teacher and let everyone solve them? (refers to students making up questions orally and other students answering them)
Design intention: Let students consolidate the knowledge of this lesson and develop their thinking through various exercises with appropriate difficulty.
Verb (abbreviation of verb) course summary
? Students talk about the gains of this class. Students, this class is very happy in the world of fractional division. Are you happy? Learning is a happy thing, and the teacher hopes that you can study happily and grow up happily in the future.
Six, homework:
Exercise after class: Page 56 of the textbook, Exercise, No.65438 +0.3.4.5.6.7.
Seven. Blackboard design:
Fractional division (1)
-Fraction divided by integer (1)4/7÷2 (2) 4/7÷3
=4 /7× 1/2 ? =4/7× 1/3
=2/7 =4/2 1
(3)8/9÷6 ? (4) 12/ 15÷4
=8/9× 1/6 = 12/ 15× 1/4
=7/24 ? = 1/5
The calculation method of dividing a fraction by an integer: dividing by an integer (except zero) is equal to multiplying the reciprocal of this integer.