Teaching plan "Fractional Division with Divider as Integer" Teaching 5 Mathematics Unit 31;
1, so that students can understand the significance of fractional division, explore and understand the calculation method of fractional division in familiar situations in daily life, correctly calculate fractional division by integers, and solve simple practical problems.
2. Let students experience the connection between fractional division and life, feel the connection between fractional division and integer division, cultivate positive learning attitude and establish confidence in learning mathematics well.
Teaching focus:
Understand the arithmetic of fractional division with divisor as integer and master the calculation method.
Teaching difficulties:
Understand the arithmetic that the decimal point of quotient and the decimal point of dividend should be aligned through learning activities.
Preparation before teaching:
Preview list, courseware.
Teaching process:
First, review the old knowledge.
1, vertical calculation
96÷3= 120÷5= 570÷6=
Step 2 fill it in
9.6 There are () in ten. Divide ninety-six tenths into three equal parts, each part is () tenths, that is, ().
Two is a few tenths. Divide 20/10 into 5 equal parts, each part is (), that is ().
Second, explore the algorithm and summarize the algorithm:
1, explore the arithmetic sum algorithm of 9.6÷3;
The courseware shows the form of buying fruit.
Teacher: What information can you learn from the table?
Please estimate the unit price of each fruit.
The students answered.
(2) I want to know the exact unit price of apples. How to calculate it?
(3) Show the preview list of students:
32 Angle =3.2 yuan
(4) When students say that vertical calculation can be used, they should be guided as follows:
We are no strangers to division, because we have studied integer division and learned how to find the quotient of two numbers vertically. Presumably, fractional division can also be calculated vertically. From this point of view, this classmate's suggestion is very good. I hope students can try the algorithm according to their previous knowledge and learning experience.
(5) Show students' vertical calculation and let them explain.
(6) Looking back at the vertical process, the teacher put forward the camera problem in the process of blackboard writing:
A: which number should be removed first, and where should I write it?
B: What do you mean by moving down 6? Where did Shang Ji write it? What do you mean?
C: How to point the decimal point and why should it be aligned with the decimal point of dividends?
(7) Revelation 1: Starting from the highest division, the decimal point of the quotient should be aligned with the decimal point of the dividend.
(8) Students write the correct calculation process in the exercise book to consolidate the algorithm.
2. Explore the arithmetic and algorithm of 12÷5;
(1) Just now we estimated that the unit price of bananas is about two yuan or more. How can I accurately know the unit price of bananas?
(2) Show the students' study list, which will be explained by the students.
(3) Reviewing the vertical process, the teacher put forward the camera problem in the process of writing on the blackboard:
A: which number should be removed first, and where should I write it?
B: What if the remaining 2 is not enough? What is 2 plus 0? What does this mean? Twenty-tenths divided by five quotients, where does it say?
C: How to point the decimal point of quotient and why should it be aligned with the decimal point of dividend?
(4) Revelation 2: If there is a remainder from the most effective division to the end of the dividend, add 0 after the remainder to continue the division. The decimal point of quotient should be aligned with the decimal point of dividend.
(5) Students write the correct calculation process in the exercise book to consolidate the algorithm.
3. Explore the theory and algorithm of 5.7÷6;
(1) Just now we estimated that the unit price of oranges is probably less than one yuan. How can I accurately know the unit price of bananas?
(2) Show the students' study list, which will be explained by the students.
(3) Looking back at the vertical process, the teacher asked questions to the camera during the blackboard writing process:
A: What if the unit is not quotient 1?
B: What if there is a surplus besides the bonus? What does it mean after adding 0? Where does Shang Ji write?
C: How to point the decimal point of quotient and why should it be aligned with the decimal point of dividend?
(4) Revelation 3: Starting from the highest digit, the unit is not enough to quotient 1, so write 0. If there is a remainder besides the dividend, add 0 after the remainder to continue the division. The decimal point of quotient should be aligned with the decimal point of dividend.
4. Compare and summarize the algorithms:
(1) Put the three problems of fractional division vertically on the same page for students to observe:
These three vertical forms are different, but there are many similarities in algorithm. Can you name a few points?
(2) After the students think independently, they communicate in groups, and the teachers patrol to listen to the communication of a group of students and make some suggestions.
(3) Collective communication and induction, the default is as follows:
(1) from the highest dividend, the integer part is not quotient 1, so you should write 0 as the complement;
(2) In addition to the last decimal place, if there is a remainder, add 0 to continue the division until there is no remainder.
③ The quotient is aligned with the decimal point of dividend;
(4) Show the calculation method of fractional division with integer divisor, and let students find out the key algorithm that best highlights the characteristics of fractional division from some similarities in students' communication. Again, the decimal points of quotient and dividend should be aligned.
(5) Check the above problems according to "unit price × quantity = total price".
Third, consolidate the exercises and strengthen the algorithm:
1, after practice:
4.2÷4= 15÷6= 0.2÷5= 3÷ 15=
(1) Students calculate independently, and the teacher knows to collect wrong examples on the spot.
(2) The teacher will project the collected examples of mistakes on the screen, so that students can observe and analyze where the mistakes are and how to correct them.
2. Complete the exercise 1 1, question 1-3.
Fourth, the class summary:
Today, we learned about fractional division in which the divisor is an integer. All the students explored a new algorithm with their own knowledge, which made us succeed in our study. Division calculation is difficult. I hope that students can practice according to their own actual situation and achieve proficiency.
Blackboard design:
The teaching goal of unit 3 "Fractional division with divisor as integer" in mathematics teaching plan
1, so that students can learn the calculation method of fractional division with divisor as integer.
2. Understand the relationship between the calculation rules of fractional division with integer divisor and integer division.
Teaching focus
Calculation method of fractional division with divisor as integer.
Teaching difficulties
Understand fractional division with divisor as integer.
teaching process
First, pave the way for pregnancy
(A) oral calculation
0.9×6 7×0.8 8.2÷4 12.5÷5 14×0.5
9.6÷6 0.7× 1 6.8÷4 4.8÷4 3.9÷3
(2) Board performance: 108÷36
(3) Question: Last class, we learned a simple calculation method of divisor as integer. Who can tell us what its calculation method is?
(4) Teacher's introduction: Today, we will continue to learn fractional division with divisor as integer.
(Title on the blackboard: Fractional division in which divisor is an integer)
Second, explore new knowledge.
(A) Teaching Example 2
Example 2: There used to be 36 tractors in Yongfeng Township, but now there are 1 17 tractors. What is the number of tractors now?
1, look at the problem, understand the meaning of the problem, and list the formula: 1 17÷36.
2. Students discuss and try in groups.
3, courseware demonstration: divisor is integer decimal division 2
The teacher made it clear that when calculating division, if there is a remainder at the end of the dividend, add 0 to the remainder to continue the division.
Step 5 practice
25.5÷6 (When calculating, a 0 should be added at the end of the dividend)
86÷ 16 (three zeros need to be added at the end of dividend when calculating)
(2) Summarize the calculation rules of fractional division with integer divisor.
Divider is a fractional division of integers, which is removed according to the law of integer division. The decimal point of quotient should be aligned with the decimal point of dividend. If there is a remainder at the end of the dividend, add 0 after the remainder to continue the division.
(3) Practice
32÷5 6 10÷6
(4) Teaching Example 3
Example 3 Calculation 1.69÷26
1, students try to do
2. Collective revision
Key question: What happens to the Chamber of Commerce when the integer part of the dividend is less than the divisor? What should I do?
Step 3 consolidate the exercise
17.92÷32 1.26÷28
Third, the class summary
What did we learn in this class? What should I pay attention to when calculating? (The unit of quotient is not enough 1, so the unit of quotient is written as 0. )
Fourth, classroom exercises.
(1) Calculate the following questions,
42.2 1÷ 18 6.6÷4 37.5÷6 435÷ 12
(2) There were only 24 TV sets in Zhang Cun last year, and there are 30 new TV sets this year. How many TV sets are there in Zhang Cun now?
(3) An elephant weighs 5. 1 ton, which is 15 times the weight of a yellow cattle. How many tons is this elephant heavier than this ox?
Verb (abbreviation for verb) homework after class
Four cars can use 35.28 kilograms of gasoline for seven days. How many kilograms of gasoline can each car save on average every day?
Sixth, blackboard design
Divider is a fractional division of integers.
There used to be 36 tractors in Yongfeng Township, but now there are 1 17 tractors. What is the number of tractors now?
1 17÷36=3.25
Now the number of tractors is 3.25 times that of the original.
Calculation rules: the divisor is a fractional division of an integer, which is divided according to the law of integer division, and the decimal point of quotient should be aligned with the decimal point of dividend; If there is a remainder at the end of the dividend, add 0 after the remainder and continue the division.