Lecture notes on mixed operation

As an educator who gives lessons to others, he should write lectures, which will help improve teachers' theoretical literacy and ability to control teaching materials. How should I write a speech? The following is the draft of mixed operation lecture I collected for your reference, hoping to help friends in need.

Lecture notes on mixed operation 1 1. Teaching materials:

"mixed operation" is the addition and subtraction learned by primary school students; On the basis of the new content of multiplication and division, the textbook creates the problem situations of "Little Bear Shopping" and "Shop Assistant", the purpose of which is to let students know that there are addition and multiplication, and the multiplication must be calculated first, and through the activities combined with specific situations, let students understand the significance of the four operations, and cultivate their ability to ask and solve problems in the process of discovering and solving problems. Make them build up confidence in learning mathematics. Gradually improve your computing ability.

Teaching goal: let students know and master the meaning of four operations, and cultivate students' problem-solving ability and teamwork spirit.

Teaching emphasis and difficulty: master the mixing operation sequence skillfully.

Second, oral teaching methods

According to the young age and intuitive thinking of the second-grade pupils, I use the teaching methods of recording, attending classes, calculating, multimedia courseware, finding problems and discussing, so that students can observe things in groups and discuss and solve problems, with the aim of creating a relaxed and happy learning environment for students and facilitating them to acquire new knowledge on their own initiative.

Third, theoretical study.

Take "multimedia courseware" as the carrier, and take observation, comparison, group discussion, reasoning application, verbal calculation and listening calculation as the main line. The purpose is to make students interested in learning and leave room for students to study and think.

Fourth, talk about the teaching process

The first link is "bringing forth the old and bringing forth the new with animated scenes"

With the animation, then the rabbit asks questions. Mother rabbit found 2 1 Chinese cabbage this morning. Animation situation can quickly focus students' emotions and thinking on the country where they have trained their auditory thinking.

The second link: grasp the supply perception and learn new lessons.

Computer demonstration "Little Bear Shopping"

(1) Buy 4 loaves of bread and 1 bottle of drinks (how much should I pay)

(2) Divide the students into groups to discuss how to make formulas, and then tell their peers what they think. Make a computer demonstration: then ask the students, "If there is addition and multiplication here, what is the first thing?" Is the calculated result the same as the original one? Ask students to discuss and try to explore, and ask them to tell their peers their ideas and algorithms. )

Students may appear: the result of pre-calculation addition is different from the original, and the result of pre-calculation multiplication is the same as the original, so as to guide students' questions. When there are multiplication and addition, multiplication must be calculated first.

Then let the students learn to be salespeople and put forward some formulas for their peers to calculate according to the computer display. The purpose is to give students a practical and personal opportunity.

Oral calculation: 3x5x1015 25x14213+7x5

8 X 3+ 16 5 X 5

Listen and calculate, 40-20 40 ten 20 30+20,

30 ten 20 30- 10 9 ÷ 3

9 X 3 2 1？ 7 X 8 56÷8

The purpose is to adjust the classroom mood and consolidate and strengthen the content just learned.

(3) According to the computer demonstration, the animated bear bought three packs of biscuits with 20 yuan's money and asked the students how much they would get back. Discuss how to make a presentation and then tell your partner what you think.

Then I integrated the analysis of the students, (giving affirmation and praise to the students who can directly list the comprehensive desktop)

Computer demonstration, 30×4 = 12 (yuan)

20- 12 = 8 (yuan) 20-4 = yuan.

Then ask the students, "Here are subtraction and multiplication. What's the first thing? Is the result the same as the original? " At the same time, let students discuss in groups, try to explore, and ask to tell their peers about their ideas and algorithms. )

Students may appear; If there is pre-calculation subtraction, the result is different from the original, and the knot of pre-calculation multiplication is the same as the original. Then guide students to "pre-calculate subtraction and multiply first"

Computer demonstration intuitively and clearly understands the contradiction between students' concrete thinking and knowledge abstraction, and at the same time brings mathematics into life, making mathematics alive, thus improving students' independent ability. At the same time, let students ask questions, discuss questions, find answers and find rules in class. Treating "classroom teaching" with "classroom activities" makes teaching and learning problematic, integrated, open, practical and democratic, creates a relaxed and happy learning environment for students, and cultivates students' willingness to participate in it personally.

Then there are some formulas on the computer for students to calculate orally:

4x3+530—4x57 16，7+2263 17+2 1 8 1+9+9 1。

35-5 X 7 80-9 5 1 16x8

Listen and calculate:

8+40 X 8 12+40 X 6 8+l9+9

35÷5 54÷9 200 1300 300 1 100 100+400 300+300 500+200 8 1 19 1 108+5+9 6 * 8+ 1r。

3 X7+9

This not only consolidates the content of learning new lessons, but also trains and improves students' oral English and listening.

This link has risen from perceptual knowledge to abstract thinking, which not only trains students' thinking ability, but also improves their language expression ability.

The third part designs two sets of questions (computer demonstration of courseware) according to students' knowledge, age and psychological characteristics, closely connecting with the difficulties of teaching content.

The first group of oral calculation: 200-9 ~ 9 700-5x660+4 59-25x25x8-4065-10+1065-3x543-5x716+2+8.

Listening calculation (courseware recording) 50i () = 5 40-() ii 20 80i 50 ÷ () =10 8l ÷ () = 9 85+() ii100.

The second group listens and counts;

Milk +640+6X7

Now she wants to give 2 1 Chinese cabbage to three rabbits. How much cabbage does each rabbit eat? (Courseware recording) and then listening and computing training (Courseware recording) 8 1÷9 9 3 54÷6 56÷8 8X9.

The purpose is to train and improve students' oral, listening and mental arithmetic abilities, mobilize students' multi-sensory learning and give full play to students' thinking ability through the knowledge consolidated by these two levels of open questions with levels, slopes and moderate difficulty.

The fourth link is the summary of the class and the extension of desire.

Ask the students to tell their peers about the gains and problems of this class, and solve the students' problems in the form of student-student communication and teacher-student communication, which not only solves the problems, but also cultivates the students' team spirit.

At the end of the course, leave students with an after-class question (computer display)

How to operate this formula of addition, subtraction, multiplication and division? what do you think? Let the students take "?" After class, students' thirst for knowledge has been extended.

Lecture Notes on Mixed Operation 2 Today, I will talk about the knowledge of mixed operation in Unit 10, Book 3 of Primary School Mathematics, Qingdao Edition. This lesson guides students to understand the operation order and master simple elementary arithmetic skills in the process of solving specific problems. On the basis of studying mathematics curriculum standards seriously, studying textbooks and fully understanding students, I am going to give lectures from the following five aspects:

First, understand the concept of new curriculum standards

Mathematics curriculum standards clearly point out that students should be presented with "realistic, meaningful and challenging" materials according to their life experience and existing knowledge, provide sufficient opportunities for mathematics activities and exchanges, guide them to acquire knowledge and skills in the process of independent exploration, and try to abstract practical problems into mathematical models and explain and apply them.

Second, analysis of teaching materials and learning situation

"Mixed operation of multiplication, addition and subtraction" is one of the important contents of "number and algebra". Teaching is based on students mastering addition and subtraction within 100, multiplication and division in the table and two-step addition and subtraction. This part is the basis for studying elementary arithmetic and solving slightly complicated problems in the future. Through the scene that tourists come to the scenic spot to buy tickets and pay bus fares, the textbook puts forward the problem solved by mixed operation and starts the study of simple elementary arithmetic knowledge. The design of this lesson still follows the problem-solving framework and understands the order of mixed operations in the problem-solving process. This arrangement, on the one hand, can help students understand the operation sequence by using realistic materials. On the other hand, it helps students to appreciate the value of operation.

Three. Teaching objectives, teaching emphases and difficulties

Combining the age of students and the existing knowledge and experience, I have established the following teaching objectives in this course:

1. In the process of solving specific problems, when you realize that there are both multiplication and addition (subtraction) in a formula, you must first calculate the rationality of the operation order of multiplication and addition (subtraction).

2. Put forward the problems that can be solved by the mixed operation of multiplication, addition and subtraction in specific situations; And can combine the specific situation, simply express the process of solving problems, and initially learn to think systematically.

3. Establish confidence in learning and feel the fun of learning mathematics.

Because the second-year students are still in the concrete thinking stage of images, the content of this lesson is concerned by students, and it is difficult to understand the operation order of "multiply first and then add and subtract". Therefore, mastering the operation sequence is the focus of this course, and it is also the difficulty of this course.

Fourth, teaching preparation:

If a class wants to be successful, it must be fully prepared. To this end, I have made the following preparations:

Make courseware (pictures of Taishan scenery, pictures of ticket purchasing scenes, pictures of drivers paying)

Teaching process of verbs (abbreviation of verb)

(A), create a situation, ask questions

1, Taishan scenery picture appreciation.

2. Teacher: Do the students like traveling? Let's go to Mount Tai with the tour group today.

Students appreciate pictures.

Teacher: We have reached the entrance of the mountain. If you are our tour guide, what do you want to know?

(Blackboard: How many people are there in the tour group)

(2) Autonomous learning and group inquiry (courseware demonstration information window 1)

Teacher: Please look at this picture carefully. Can you find the information you need to solve the problem?

1, Teacher: The students observe very carefully. Based on this information, can you find out how many people are in the tour group? Please try it and share your thoughts in the group.

2. Teacher: Who can come up and talk about your method?

3. What are the similarities and differences between these students' calculation methods?

4. Teacher: When there are addition and multiplication in the formula, you should calculate the multiplication first and then the addition.

5. Teacher: Which method do you like best and why?

Students may answer after thinking:

How many people are there in the tour group?

How many tickets do you need? ……

Students look for the information they need according to the pictures:

The tour guide said, "A group of 9 people has been divided into 4 groups."

The tourist said, "There are five people left." ……

(3), reporting and communication, evaluation and questioning.

1. Students try to solve problems and exchange their ideas and algorithms in groups.

Students explain their ideas and algorithms on the blackboard. The possible methods are:

9+9+9+9+5

Let's start with 9×4=36 (person)

Count 36+5=4 1 (person)

9×4+5

5+9×4……

Students think independently and communicate with the whole class.

The key point is clear: these formulas are to find four groups of people first, and then add up the remaining people. That is, multiply first, then add.

2. (Courseware shows the driver taking money to pay)

Teacher: What do you see in the picture?

What other math questions do you ask?

(blackboard writing: how much should I take back)

Teacher: Please try to solve it yourself.

3. Teacher: Do you have any questions about this classmate's method?

Guide the students to look at the pictures and say: There is a sign that says: Small cars: every 4 yuan, large cars: every 6 yuan.

The driver had to pay the parking fee for three cars, and he took it out to 50 yuan. ……

Questions that students may ask are:

How much is a * * *?

How much do you want back? ……

Students do it independently. The teacher asked students with different algorithms to write on the blackboard and explain their ideas. Possible algorithms:

(1)4×3= 12 (yuan)

50- 12 = = 38 (yuan)

(2) 50-4× 3 = 38 (yuan)

Students ask questions and answer each other.

Can you look at the pictures carefully and look for useful information?

Encourage students to solve problems in different ways, and pay attention to whether students can clearly explain the meaning of the formula.

Deepen the understanding of knowledge by asking questions and solving doubts.

(4), abstract generalization, summary and promotion.

1, Teacher: Please observe these formulas on the blackboard. Can you find similarities?

2. Teacher: When there are multiplication and addition and subtraction, what should I count first?

Students speak freely after observation: there are multiplication in the formula, both of which include multiplication and addition or multiplication and subtraction.

The first is multiplication.

Teacher: What do you think you have gained from this course, or what you have done better?

(five), consolidate the application, expand and improve.

Teacher: Please complete the second question on page 102 of the textbook.

Students do it independently. When correcting, talk about the operation order of each question.

Pay attention to whether you can master the order of multiplication, addition and subtraction.

Attachment: blackboard design

Multiplication plus (subtraction) mixed operation

There are multiplication and addition (subtraction) in the formula. Calculate multiplication first.

In the teaching of this course, I follow the students' cognitive law, take the quality education thought as the guidance, take students' active participation as the premise, take autonomous learning as the way, take cooperative learning as the form, and focus on cultivating innovative spirit and practical ability to design the above teaching links. Due to the limited level, there must be many shortcomings. Please criticize and correct me. Thank you! )

Lecture notes on mixed operation 3 I. Talking about teaching contents

What I'm talking about today is the first lesson of Unit 3 "Mixed Operation" published by Jiangsu Education Publishing House.

Second, say teaching material analysis.

The teaching content of this course is based on the fact that students have basically mastered four operations of integers, and can perform two operations at the same level, such as addition, subtraction, addition and subtraction, multiplication, division, multiplication and division, but the operation order is calculated from left to right. In order to break the stereotype of students, the teaching materials are realistic and interesting, and the spiral way is adopted to let students understand the order of mixed operations from the simple to the deep. The study of this part also lays the foundation for the mixed operation of decimal and fraction in the future.

Third, talk about teaching methods and learning methods.

According to the curriculum standards and teaching content, combined with students' reality, I think this class should achieve the following teaching objectives:

(1) Let students know the comprehensive formula in combination with the problem-solving process, master the order of multiplication and the mixed operation of addition and subtraction, and be able to calculate correctly.

(2) Let students go through the process from step-by-step formula to solving problems with comprehensive formula, realize that comprehensive formula can solve practical problems in two-step calculation, and feel the diversity of problem-solving methods.

(3) Let students feel the close relationship between mathematics and daily life in the process of students, and enhance their awareness of applied mathematics.

Combining the compilation of teaching materials and the characteristics of this course, I think

Teaching emphasis: display the format of calculation process with recursive equation.

Teaching difficulties: master the order of multiplication and the mixed operation of addition and subtraction, and be able to calculate correctly.

Four, said the teaching aid preparation:

The courseware shows the P30 theme map and exercise map.

Verb (abbreviation of verb) oral teaching method and learning method

Ye Shengtao, a famous educator, said: It is important to teach the law, but not to teach it. In this class, I use situations, life experiences and other methods to make students turn hard study into happy study.

Students are the main body of learning, and their participation status and degree are important factors to determine the teaching effect. Guide students to carry out inquiry learning activities through observation, comparison and summary.

Sixth, talk about the teaching process.

In order to show that students are the main body of learning activities, I take students' learning as my foothold. The following five teaching links will be designed:

First, create shopping situations and solve problems independently.

Situation is the easiest way to stimulate students' interest in learning. On Sunday, Xiaojun and Xiaoqing came to the store together and wanted to buy some school supplies. Let the students observe carefully. What school supplies are there in the shop? What is their unit price?

According to the information provided in the picture, combined with their own shopping experience, let the students ask the question of one-step calculation. one

Students ask questions and the class answers.

Design intention: Mathematics comes from life. First of all, present students' familiar shopping scenes, ask math questions, and let students realize the connection between mathematics and life.

Secondly, the operation sequence of mixed operations including multiplication and addition is discussed.

This paragraph is the focus of this lesson:

In order to master the operation sequence, the learning of mixed operation is combined with practical problems. Stimulate students' desire to learn, let them discover methods and summarize laws. It is divided into five steps:

1. Courseware shows: Xiaojun "buys 3 notebooks, 1 schoolbag. Can you help me calculate how much a * * *? " Most students may make a step-by-step formula, and some students may make a comprehensive formula. At this time, let the students report step by step, and I will write on the blackboard in time: How much is three notebooks first? Display formula

5×3= 15 (yuan) a * * *, how much is it? 15+20 = 35 (yuan)

Step 2 Look at the picture to solve the problem

Question: To ask "How much is a * * *", what should be calculated first? Can you combine these two formulas into one? Try to list the time and space of the comprehensive formula for students, allow discussion and exchange, and then write on the blackboard: 5× 3+20.

3. Column synthesis formula: My finger is a formula similar to 5× 3+20, which is a two-step formula composed of two formulas. We call it a comprehensive formula. In this comprehensive formula, which step should be calculated first? What is the number? What does this number mean? Let the students understand the meaning of the comprehensive formula. I once again sum up and point out that when calculating the comprehensive formula, in order to see the operation process clearly, the results of each calculation are generally written and expressed by recursive equations. Introduce recursive representation to students. Then let the students use recursive equations to consolidate the connection.

4. There are various methods: if we list the comprehensive formula as follows: 20+5× 3, is it ok?

Let the students make it clear: how much is a * * *, which is the total price of a schoolbag and three notebooks, just in line with the meaning of the question.

In this comprehensive formula, which step should be calculated first? What is the number? Why do we have to calculate 5×3 first?

Let the students imitate the above writing format for offline calculation, and the teacher will patrol to help the poor students and grasp the wrong resources.

5. Exhibition assignment: Guide students to think: Through the calculation of this comprehensive formula, let students talk about what to pay attention to when calculating.

Summary: In a formula with both multiplication and addition, whether multiplication is before or after, multiplication must be calculated first, and then addition must be calculated. There are two or more operations like this, which are usually called mixed operations. In this lesson, we will learn how to perform mixed operations. (Title on the blackboard: Mixed operation)

Design intention: Mathematics class is abstract and sometimes even boring, especially the calculation class. In order to stimulate students' interest, students are given space and time to think in this link design, so that students can have more time to participate, express more opinions and satisfy their self-confidence.