Teaching Design for "Dividing Two or Three Numbers by Whole Tens"

"Dividing two or three digits by whole tens" Teaching Design Part 1

Teaching content: Dividing two or three digits by whole tens (the quotient is one digit), textbook Pages 1-2

Teaching purposes:

1. Let students experience the oral calculation method of dividing whole tens or hundreds and tens of numbers by whole tens and two or three digits The exploration process of the written calculation method of dividing by whole tens, the ability to correctly perform oral and written calculations, and the ability to check calculations; and the ability to perform simple time unit conversions.

2. Allow students to build self-confidence in learning mathematics while actively exploring and acquiring mathematical knowledge, and be able to actively communicate their thoughts on learning with classmates, and accumulate experience in cooperation and communication with others.

Teaching focus: Guide students to independently explore oral and written calculation methods of dividing by integers.

Teaching difficulties: Think independently and communicate and discuss the calculation process of written arithmetic, especially the writing position of quotient.

Lesson schedule: ***1 lesson in this section, this lesson is the first lesson

Lesson type: New teaching

Teaching process:

1. Introduction to the conversation

Students, the new semester has begun again. What preparations have you made for the new semester? The teacher has also made some preparations for you, please see——

< p> Show the flipchart: The teacher buys a notebook in the mall.

2. Explore oral arithmetic methods

1. Teaching examples.

(1) Obtain information from the situation.

Question: What information can you understand from the picture? (The teacher bought 60 math books, each packed into a pack of 20 books)

What kind of information can you come up with based on this information? Mathematics problem? (How many packages can it be made into?)

How to calculate the formula?

The students said the formula, and the teacher wrote on the blackboard: 60÷20=

( 2) Work in groups to explore oral arithmetic methods.

Conversation: First, calculate the number orally by yourself, and then share your oral calculation method with the group. After students do the calculations orally, they communicate in the group.

(3) Group report and exchange.

Question: What is the result of your oral calculation?

What do you think?

Students report, and the teacher randomly writes on the blackboard.

Students answer and explain their reasons to further understand the arithmetic.

(4) Complete the answers to the questions based on the students’ answers.

Complete writing on the blackboard: 60÷20=3 (packages)

Answer: It should be made into 3 packs.

2. Oral arithmetic practice (do question l of "Think, Do, Do").

Conversation: Now use your favorite method to do a set of oral arithmetic exercises (show)

4÷2 9÷3 12÷6 40÷8

< p>　40÷20 90÷30 120÷60 400÷80

Students count in groups.

(1) Students will talk about the oral arithmetic methods for the questions in the 1st and 3rd groups.

(2) Question: Is divisor the easiest way to divide integers verbally? (Remove the 0 at the end of both the dividend and the divisor, and use the multiplication formula to calculate)

Three , Explore written calculation methods

1. Show the topic.

Conversation: Just now we used our favorite method to practice oral arithmetic. Students, please observe how these questions are different from the division we have learned before? (The divisor is an integer ten)

Today we are learning "oral arithmetic when the divisor is an integer ten". (Blackboard question) This type of question can also be calculated using written calculations. (Supplementary topic "Calculation with pen") Do you know how to calculate? Want to give it a try?

2. Independently explore the written calculation method of 60÷20.

Let students try independent writing calculations.

The teacher inspects and understands the students’ different writing methods.

3. The projection shows students different calculation methods and the correct writing position of the communication quotient.

First communicate fully, and then write on the blackboard.

Make students clear that because there are three 20s in 60, this "3" represents the number of 20s, which is three ones, so 3 must be written in the ones digit of the quotient, but not in the tens digit of the quotient.

4． Try to calculate and check 96÷20, 150÷30.

Name the board to perform, and other students will complete it independently in their exercise books.

Collectively revise and discuss issues that should be paid attention to when communicating calculations:

(1) Pay attention to the writing position of the quotient. Key discussion: Why should the quotient of 150÷30 be written in the ones digit of the quotient?

(2) Note that the remainder is smaller than the divisor.

(3) Pay attention to confirm whether your written calculation results are correct by checking.

Summary: The students mastered the written calculation method of dividing the divisor by an integer through independent exploration, and summarized the issues that should be paid attention to during calculation through communication.

IV. Consolidation exercises

1. Do the second question of “Think about it, do it”.

First do the questions independently in the textbook, and then revise them collectively as a class. If an incorrect question is found, analyze the cause of the error together.

2. Do question 4 of “Think about it, do it”.

(1) Fill in the textbook independently.

(2) Question: What do you think when solving the problem "180 minutes = ( ) time"? How to calculate the formula? What is the number?

Put "seconds" How to convert "minutes" into "hours"?

3. Do question 6 of “Think about it, do it”.

(1) Read the question silently.

(2) Name the conditions and problems of the topic.

(3) Solve independently

(4) Revise in the group.

5. Classwork

Questions 3 and 5 of “Think about it, do it”.

6. Summary of the whole lesson

Question: What content did you learn in this lesson? How many digits did you calculate the quotient of the question? [Complete the question and write on the blackboard: (The quotient is Single digit)] What did you gain? "Dividing two or three digits by whole tens" Teaching Design Part 2

Teaching content: Example 2 and Exercise 13 on page 79 of the textbook.

Teaching objectives:

1. Through exercises, further consolidate students’ oral arithmetic methods for dividing integers by ten and counting hundreds and tens.

2. Consolidate students’ estimation methods through exercises.

3. Further develop students’ analogy and oral language expression abilities.

Important and difficult points in teaching:

Key points: Correctly master oral arithmetic methods and be able to do oral arithmetic correctly.

Difficulty: Correctly master the estimation of two-digit division and be able to estimate correctly.

Teaching aid preparation: digital card apple tree and digital apple card small blackboard

Teaching process:

1. Create situations to introduce problems

In the last class, students helped the teacher distribute balloons. The teacher knows that you are good students who are willing to help others. Today, the teacher also has 120 colorful flags, and each class is given 30 flags. What math problems will you find?

The teacher writes on the blackboard based on the students’ answers: 120÷30=

Teacher: Is an expression like this the same as the division we learned in the previous class? How should we calculate orally? Today we will study the division of whole hundreds into whole tens (blackboard writing topic).

(Design intention: In this lesson, I created a mathematical situation close to the actual life of students, such as the Jiepeng Qi Colorful Flag, to allow students to experience raising mathematical problems. This will not only help students understand and master calculation methods , and can enhance students' interest in learning mathematics.)

2. Exploring communication and solving problems

(1) Teaching the oral arithmetic method of dividing whole numbers by hundreds.

1. Independent exploration:

Teacher: Ask students to try to calculate. Are you confident you can solve the problem?

Students think independently and try to practice. Teachers patrol to understand students' learning status and provide timely guidance.

2. Interactive communication:

(1) Group communication

The teacher put forward several requirements: the group leader is responsible for organizing, and each student speaks in order. Speak; the recorder takes notes.

Students interact and communicate and present their own solutions to problems in the group. Compete to see whose idea is better. Form group opinions.

3. Whole-class communication:

The teacher organizes students to report on the algorithms of each group, and the teacher provides guidance on key links for improvement.

(1) It can be explained with physical objects. Use the method of dividing small sticks, divide one point, and replace the colorful flags with 120 small sticks. Taking 30 sticks as one portion, it can be divided into four parts, so 120÷30=4.

(2) There are 4 30s in 120.

(3) 120÷30 becomes 12÷3=4 (division within the table) by removing all the following 0s.

(4) 4 times 30 equals 120, so 120÷30=4, our team just calculated it orally. Our group uses the relationship between multiplication and division.

Teacher: Your ideas are great. Teacher is proud of you. Applaud yourself!

(2) Teaching how to divide hundreds to tens and using estimation awareness.

Can you still accept the challenge? Use a small blackboard to display the questions

122÷30≈120÷28≈

①What are the similarities between our two questions and the previous ones

②We What to do, try it! See who has the best idea!

③Do it yourself first, and then share your ideas

(3) Guide students to come up with the method of oral arithmetic for dividing whole numbers by hundreds.

Teacher: Please observe and compare the three questions. What similarities and differences do you find? Draw a conclusion

(Summary: The oral calculation method of dividing a hundred by an integer ten is usually to calculate the dividend and divisor as a hundred divided by an integer ten, or think of the division method based on the division method in the table and looking at the multiplier relationship.)

(Design intention: This learning method makes students truly the masters of learning. In teaching, I let students operate, try, and explore methods. And on this basis, timely organization Discuss and communicate to enhance students’ understanding of calculation processes and improve students’ understanding of arithmetic. It creates a space for students to actively explore mathematical knowledge and gradually introduces students to the division of integers by tens. The importance of oral arithmetic. Reflects the diversity of operational reasoning)

3. Consolidate and improve application internalization

1. The teacher presents the number cards.

See who can count the most within the specified time. Then revise the answers and ask students to tell you how you did the calculations orally? And talk about the arithmetic process.

30÷10=60÷30=80÷40=240÷60=

210÷70300÷50=270÷90=630÷70=

2. Driving a train

(Complete the remaining questions in Question 1 of Exercise 13 on page 80 of the textbook).

180÷30=240÷40=420÷60=

184÷30=240÷37=420÷58=.

3. Picking wisdom, who can pick the most.

(1) Show question 3 of Exercise 13 on page 80 of the textbook.

Let students understand the meaning of the questions and complete them independently. Give wisdom fruit rewards to students based on their completion status

(2) Question 5 of Exercise 13 on page 80 of the textbook.

Students understand the meaning of the question, list the formulas independently, and communicate collectively.

How are you doing? How many fruits of wisdom have you harvested?

(Design intention: In mathematics teaching activities, students are allowed to actively participate in them. During the exercises, I designed "number cards" to "see who can calculate the most accurately" and "open" within the specified time. "Train" and "Picking the Fruits of Wisdom", students are willing to accept it, allowing students to learn to learn in happy learning, and at the same time giving each student more practice opportunities, allowing students to practice oral arithmetic in a pleasant atmosphere and improve their oral arithmetic ability.

)

4. Review, organize, reflect and improve

What knowledge did we learn today? What do you gain?

Blackboard design:

Oral calculation of dividing hundreds into tens

120÷30=4 (pieces)

Answer: Can be divided into 4 classes

122÷30≈4

120÷28≈4

Post-teaching reflection:

Finished After this class, I felt "surprisingly" smooth. It's easy to succeed in the previous class, but there will always be flaws. But "surprising", of course, is also strange. Why do you say this? The reason is that all students know it, almost without being taught. hehe! Unexpected success already shows that there is failure lurking in it.

Some of my thoughts on this lesson after class:

The first is the determination of the teaching objectives. In principle, the teaching objectives are determined based on the content of the teaching materials, but since the content of this class is relatively simple and easy for students to master, I feel that the teaching objectives should not only be determined based on the content of the teaching materials, but also the characteristics of the students and their characteristics. their knowledge base.

The second is to grasp the key points of teaching. Since students know what it is and can do it, they must know why it is done – how to do it? What is more difficult to grasp in computing teaching, especially oral arithmetic teaching, is the scale of skills and thinking. In oral arithmetic teaching, knowing what is happening is the mastery of calculation skills, and knowing why is the exercise of thinking level. Therefore, the teaching focus of this class is to know the reasons, which is to train students in the process of oral calculation and reasoning. From this perspective, I did not grasp this teaching focus in this class.

Through the teaching of this class, I have a deeper understanding of the important factors of students in preparing lessons, and the training of thinking is the focus of students learning mathematical knowledge. Seeking peace and stability in the classroom seems to be a success, but in fact it hides many failures. "Dividing Two or Three Digits by Integers" Teaching Design Part 3

Teaching objectives:

1. Learn to divide integers by integers and the oral arithmetic of hundreds and tens. method.

2. Experience and explore the oral calculation methods of dividing integers by tens, hundreds and tens, and find the optimal method through your own feelings.

3. Be able to perform oral calculations skillfully.

4. Experience the joy of success through your own exploration of oral arithmetic methods.

Teaching focus:

Master oral arithmetic methods.

Teaching difficulties:

Explore the arithmetic methods by yourself, and be able to connect them with the division methods in the table to make the knowledge systematic.

Teaching process:

1. Introduction

1. Counting: 10 10 numbers (raw numbers) Question: How many 10s are counted in 40? What about 60? …

20 20 numbers (raw numbers) Q: How many 20s were counted in 40? What about 80? …

40 40 numbers (raw numbers) Q: How many 40s are counted in 40? What about 120? What about 240?

2. Write the formula based on the counting just now

How many 10s did you count in 40? Can you do calculations? (Student and lecturer board: 40÷10=4) How many 20s are there in 40? How many 40s are there in 120? What about 240?

(Written on the blackboard: 40÷20=2 120÷40=3 240÷40=6)

2. Expand

(1) Example 1

p>

1. Independent exploration: How is 40÷10=4 calculated? Can you explain your thoughts in more ways?

2. Group communication: First share your ideas in the group and see if your ideas are the same as those of other children.

3. Whole class communication: report by name

(1) 4 tens ÷ 1 tens = 4

(2) 4 10s is 40, So 40÷10=4

(3) 40÷10 becomes 4÷1=4 after removing all the zeros.

(4) 4 times 10 equals 40? So 40÷10=4

(5) may also be explained by physical objects.

4.: The children are really amazing. They have come up with so many ways to solve this problem. But there are so many ways, which one should I choose? Why?

5. Give it a try: (1) What about 40÷20? How to calculate student reflection report

(2) Quick answer: Teacher’s response: such as 30÷10, 60÷30, etc.

(2) Example 2

1. Choose a calculation: 120÷40 240÷40

2. Report: How did you calculate? May have different ideas.

3. Question: What are the similarities and differences between Example 1 and Example 2?

Different: one is to divide integers by tens, and the other is to divide integers by hundreds or dozens.

Same: The oral calculation method is the same.

Project topic: oral calculation of dividing integers by tens and hundreds and tens.

3. Consolidation exercises

1. Do the math

3÷1 6÷3 35÷5 63÷9

30 ÷10 60÷30 350÷50 630÷90

Work independently and report individually.

Look for the similarities and differences between the upper and lower questions. (Contact with the division method in the table to form a systematic knowledge.)

2. Competition practice: see who can calculate correctly and quickly.

60÷20 80÷40 360÷60 420÷70

90÷30 50÷10 210÷30 560÷80

3. Chapter 1 in the book Page 41 No. 3, 4. Work together and proofread as a group

4. Improve practice: see who writes more.

　( )÷□0=16

　 (1) Give 1 minute to write.

(2) Reporting

(3) Rules: How can I write faster and write more?

IV. Classroom

What do you want to say in this lesson? Talk about how you learned the content and what were the results of your learning? (Tell me about your learning feelings and experiences)

5. Classwork:

Page 22 of "Workbook".

6. Blackboard design:

Oral calculation of dividing integers by tens, hundreds and tens

40÷10=4 120÷40= 3

(1) 4 tens ÷ 1 tens = 4 240 ÷ 40 = 6

(2) 10 is 40, so 40 ÷ 10 = 4

(3) 40÷10 becomes 4÷1=4 after removing all the zeros.

(4) 4 times 10 equals 40? So 40÷10=4 12÷4=3

4÷1=4 "Two or three digits divided by whole tens" Teaching Design Part 4

Teaching content:

Questions 5-10 of Exercise 9.

Teaching purposes:

To enable students to consolidate that the divisor is an integer and the quotient is a one-digit division, and master the positioning of the quotient and the rules that the remainder is smaller than the divisor.

Teaching focus:

Consolidate that the divisor is a division of an integer with a quotient of one digit.

Teaching difficulties:

Master the positioning of business.

Teaching key:

Proficient in the positioning of quotients and the rule that the remainder is smaller than the divisor.

Teaching process

1. Review.

1. What is the maximum number that can be filled in each bracket below?

　20×（）＜850×（）＜18030×（）＜96

60×（）＜48870×（）＜41240×（）＜98

2. Oral calculation.

100÷20350÷70400÷50400÷80

80÷80÷60540÷9040÷10

3. Written calculation.

(The whole class practices together, four people perform on the board)

272÷8160÷50240÷80320÷40

Comment on the board performance and say how to divide integers into multiple digits The positioning of the business and the method of testing the business first.

2. Guiding practice.

1. Banquet: 196÷60.

(1) Quotient positioning: If the divisor is a two-digit number, first look at the first two digits of the dividend. If the first two digits are not enough to divide, look at the first three digits. The position of the quotient is set at the ones digit of the dividend. .

(2) Trial quotient: 60×()<196, find the quotient 3.

(3) Product: The product of the quotient 3 times the divisor is written below the dividend.

(4) Remainder: Subtract the product of the quotient and the divisor from the dividend, the remainder is 16.

(5) Test: The remainder 16 is less than the divisor 60, and the quotient 3 is appropriate.

2. Oral calculation: 30×()<24570×()<36460×()<435

3. Homework.

Do questions 5-10 of Exercise 9. "Two or three-digit numbers divided by whole tens" Teaching Design Part 5

Teaching purposes:

1. Enable students to initially master the test method of division by integers and the writing method of vertical expression, laying the foundation for teaching division when the divisor is any two-digit number.

2． Through group learning, students can develop their ability to actively participate in learning and communication.

4． Enable students to receive patriotism education.

Teaching focus:

Determine the location of the business and the method of trial business.

Teaching difficulties:

Correctly determine the position of the supplier

Teaching process:

1. Communicate knowledge and establish connections

1. Oral arithmetic

60÷30 120÷40 720÷90

207 35÷8 600÷4

2. What is the maximum number that can be filled in the brackets?

30×( )＜200 40×( )＜270

3. Let’s do some calculations and talk about our thoughts.

　608÷8 2367÷4

2. Solve problems and explore new knowledge

Now please ask the students to help the teacher solve a practical problem.

1. Here is a sample question: Our school has selected 60 students to visit the aviation model exhibition. Based on reality, how many people do you want to form a team that is both reasonable and beautiful? How many teams can they form?

(1) Group research and design plan, teacher inspection and guidance.

(2) Group report and exchange. Tell me what you think and how you calculate it verbally?

Choose two realistic calculations to write on the blackboard: 60÷20=3 (team) 60÷30=2 (team)

We just calculated the result orally, how to do it in vertical form What about calculations? In this lesson we will learn pen arithmetic division and blackboard writing topics.

(3) Let students choose one of them and do it vertically.

(4) Combined with the problems that arise in students’ calculations, revise and summarize the writing format of divisor for two-digit division.

(5) Do it. After students finish, talk about where the quotient should be written first and the vertical writing format.

2． Teaching example 2.

Show 200÷30=

(1) Students think independently and solve problems in groups.

(2) Student report and exchange.

(3) Teacher summary algorithm.

(4) Do question 1. Let’s first talk about where the business should be written and why. After finishing, talk about how to come up with the quotient and vertical writing format.

3. What are the differences between the examples and exercises? (Blackboard writing topic)

How should we deal with such a question?

5. Do it and do question 2.

3. Comprehensive exercises to deepen understanding

Exercise 9 questions 1-4.

"Dividing two or three digits by whole tens" Teaching Design Chapter 6

Teaching content: Examples 3 and 4 on page 37

Teaching purpose: To enable students to master division by whole tens The oral arithmetic method of hundreds, whole tens and one-digit quotients enables correct oral arithmetic and cultivates students' cooperation through group learning.

Teaching focus: To enable students to master the oral arithmetic method of dividing whole tens by whole hundreds and quoting single-digit numbers by whole tens.

Teaching difficulties: Ability to perform oral arithmetic correctly.

Teaching process:

1. Independent discussion and understanding of methods

1. Create a scenario and study Example 3.

(1) Given the conditions in Example 3, ask: How many teams do you think are reasonable and beautiful? Teachers study selectively based on student responses.

(2) First study 60÷10, let students take out the prepared sticks, and discuss how to calculate orally.

(3) Group exchange of oral arithmetic methods.

(4) Method.

(5) Discuss the oral arithmetic methods of 60÷30 and 60÷20. What do you think?

(6): The above three questions all look at the tens that are 60, then the tens divided by 60 is the number.

(7) Do it.

2. Apply transfer and study Example 4.

(1) Show Example 4, students list the formulas, and discuss the algorithm in groups.

(2) The group reports the results.

(3) Do it and share your thoughts.

2. Practice and questioning

1. Exercise 8, question 6, calculate first and then discuss the relationship.

2. Questions 7 and 8.

3. Questions 9 and 10.

Writing on the blackboard:

Oral division (2) Divide by integers

60÷10=6150÷50=3

Think : 6 10s are 60. Think: 3 50s are 150.

60 divided by 10 is 6150÷50=3

60÷20=3

3 A 20 is 60. 60 divided by 20 is 3. "Two or three-digit numbers divided by whole tens" Teaching Design Chapter 7

Teaching purpose: To enable students to initially master the five-digit quotient test method, and be able to use this method to correctly calculate the division of quotients by two-digit numbers Single digit pen arithmetic division.

Teaching focus: Master the five-input test business method and be able to calculate correctly.

Teaching difficulties: methods of trial and adjustment.

Teaching process:

1. Review communication and establish connections.

1． What is the maximum number that can be filled in the brackets?

　60（）＜26280（）＜453

　2. Fill in ＜ or ＞ below.

475250693200

3. The numbers below are each close to dozens.

　293768

2. Independent exploration and understanding of methods

1. Study example 5.

(1) Create scenarios and ask questions.

On Sunday, your mother will take you to Xinhua Bookstore to buy books. How many books can you buy for 90 yuan? Did you know?

(2) After students think, ask a classmate to tell everyone.

(3) The teacher knows the unit price of the book and shows a science and technology book for 29 yuan. How many books can he buy for 90 yuan? How much money is left?

①Students list calculation formulas, 9029, answer them independently, and discuss and solve problems in groups.

②Student report and exchange. The teacher writes the two test business processes on the blackboard based on the students' answers, and then asks the students to observe and compare. What will they find? How easy is it to compare the two methods?

(4) Do the above on page 49.

2. Study example 6. Show 27838=

(1) Let students work independently, and discuss and solve problems in groups.

(2) Student report and exchange.

(3) The teacher writes out the process of trial and adjustment based on the students’ answers.

(4) Do the following in Example 6.

3. Let students carefully observe Examples 5 and 6 and the business trial process in Doing One to see what they can discover. Students discuss thoroughly.

4． Teacher's summary: When the numbers in the ones digit of the divisor are 5, 6, 7, 8, and 9 respectively, under normal circumstances, you can remove the number in the ones digit of the divisor, and at the same time advance the previous digit by one, and treat the divisor as a sum. It's close to an integer to test quotient. The tried quotient should be multiplied by the divisor. If the product is larger than the dividend or the remainder is larger than the divisor, it means that the tried quotient is inappropriate and the quotient needs to be adjusted; if the product is equal to or less than the dividend and the remainder is smaller than the divisor, it means that the tried quotient is not suitable. quotient is appropriate.

5. Comparative exercise: 8932=8939=

(1) After writing, discuss in a group what is the difference between the trial business processes of these two questions?

(2) Student report and exchange.

6. Teachers and students summarized the method of testing quotient: the divisor is the division of two digits. Generally, the rounding method is used, and the divisor is regarded as an integer close to it to test quotient. The divisor is rounded and then tested, because the divisor becomes smaller. , the quotient tends to be too large, so the quotient needs to be changed to a smaller one, and the divisor of five is added later to test the quotient. Because the divisor becomes larger, the quotient tends to be too small, so the quotient needs to be changed to a larger value.

3. Apply methods and strengthen knowledge

Do questions 1---4 of Exercise 11

1. For question 1, first ask students to verbally test the divisor as tens, and then calculate.

2． Question 2 should be answered orally by one student.

Writing on the blackboard:

Dividing a one-digit quotient by a number close to an integer

Example 5: 9029=3...3 (yuan )Example 6: 27838=7......12

　37

　29) 9038) 278

　87266

　312