How many young trees are there in the first volume of the third grade mathematics of Beijing Normal University?

# Lesson Plan # Introduction The teaching content of "How many small trees are there" is based on students' learning and mastery of multiplication in the table. It also lays a foundation for learning to multiply two or three digits by one digit in the future. I have prepared the following lesson plans, hoping to help you!

Tisch

Teaching objectives:

Explore and master the oral calculation method of integer ten and integer hundred multiplied by one digit, and you can do oral calculation correctly.

Teaching focus:

Explore and master the oral calculation method of multiplying integer ten and integer hundred by one digit, and calculate correctly.

Teaching difficulties:

According to the specific situation, cultivate students' awareness and ability to ask and solve problems in the process of discussing and solving practical problems.

Teaching tools:

courseware

Teaching process:

First, create situations and introduce new lessons.

The teacher shows the courseware (picture of book P2)

Teacher: What information do you see from the picture?

Health 1: three bundles of young trees.

Health 2: There are 20 small trees in each bundle.

Teacher: Can you come up with any math problems solved by addition or multiplication?

Health 1: How many small trees are there in a * *?

Health 2: How many small trees are there in the two bundles?

Health 3: How many young trees are there in two bundles than in one bundle?

Teacher: Everyone's questions are very good. Today we are going to learn how many small trees there are.

Write on the blackboard-how many small trees are there?

Second, explore new knowledge and discuss algorithms.

Teacher: How can we solve this problem?

Health 1: Add

Health 2: Use multiplication.

Teacher: How to calculate?

Health 1: 20+20+20 = 60

Health 2: 20× 3 = 60

Health 3: 20× 2+20 = 60

Blackboard writing algorithm

Teacher: Why is 20×3=60?

Health: You don't need to look at the "0" after 20, because 2×3=6, and adding a "0" after multiplying 6 equals 60.

Teacher: That's a good idea. Which of the three methods do you think is the simplest?

Health: 20×3=60 This method is the simplest.

Teachers guide students to master the calculation and application of integer multiples of ten.

Third, the application of basic exercises and new knowledge.

Teacher: Let's see how many trees there are in 4 bundles. How about five bundles?

answer

Teacher: Look at these formulas. What did you find?

80×4 6×7

80×4 6×70

800×4 6×700

Let students find similarities and differences.

Fourth, expand practice and apply new knowledge.

Try question 3 and practice questions 1 and 2.

Verb (abbreviation of verb) course summary

What have we learned in this class and what have you gained?

Distribution of intransitive verbs

Workbook exercises 2 and 3.

extreme

Teaching objectives:

1. Explore and master the oral arithmetic methods of integer ten, integer hundred and integer thousand times one digit, and experience the diversity of algorithms.

2. Cultivate students' awareness and ability to ask and solve problems in the process of discussing and solving practical problems.

3. Further feel the connection between mathematics and life.

Teaching material analysis:

This is the first lesson of the new semester on the basis that students have mastered the multiplication formula skillfully last semester. The textbook uses the specific situation of three bundles of small trees to guide students to further explore a verbal calculation method of multiplying numbers by whole ten, whole hundred and whole thousand in activities.

Compared with the previous textbooks, the new textbooks reflect the process of mathematization more. It fully embodies the concept of curriculum standard based on students' existing life experience; Pay more attention to students' knowledge background and personality differences; Encourage students to think independently, put forward different calculation methods and experience the diversity of algorithms; Provide students with sufficient opportunities to engage in mathematics activities and strive to make students actively construct their own knowledge.

Teaching process:

First, create situations and ask questions.

1. Teachers use multimedia to display teaching situation maps and guide students to observe.

Teacher: Students, do you know the benefits of afforestation to human beings? Our school plants trees every year. Let's take a look at the math problems in tree planting today.

The design aims to create a familiar life situation of tree planting for students, closely link mathematics with real life, and educate students on environmental protection. )

Please observe the picture carefully and tell your deskmate what you see. How many bundles of young trees are there? How many trees are there in each bundle? ) What math questions would you ask?

Guide the students to ask "How many trees are there in a small tree?" .

The design is intended to cultivate students' awareness and ability to ask and solve problems in combination with specific situations. The design of such a link is mainly based on the fact that students have entered the third grade and can collect information from pictures. Teachers let students observe by themselves, which is also a strategy to cultivate students to learn to learn. )

Second, solve problems and explore oral calculation methods

1. Answer independently.

Students list the formula of 20×3 and try to calculate it.

2. Group communication.

Ask the students to talk about the meaning of their listed formulas in the group, and then talk about the calculation method.

(Design intention: Teachers let students explore the oral calculation method of multiplying integers by one digit, and cultivate students' independence and flexibility of thinking through independent thinking, group discussion, exploring various algorithms and communicating with others. )

3. Communicate with the whole class.

The representative of the group made a speech and came to the conclusion that 20 in 20× 3 = 60 represents 20 trees in each bundle, 3 represents 3 bundles, and 60 represents a * * * with 60 trees. Students may come up with the following calculation method.

(1)20×3 is the sum of three twenties: 20+20+20 = 60;

(2) Because 2× 3 = 6 and 20× 3 = 60;

(3) 20 can be regarded as 10×2, so 20×3 can be changed into 10×6.

As long as students' calculation methods are correct, teachers should encourage and praise students and let them choose their favorite methods to calculate.

(Design intention: The whole class communication reflects the diversity of students' algorithms, making it easier for students to choose their favorite calculation methods and achieve the purpose of algorithm optimization. )

Solve the problem.

How many trees are there in four bundles of small trees? How about five bundles? Please try to solve it first, then communicate in groups and report to the class.

The design intention is to enhance students' application awareness and improve their ability to solve problems through the application of knowledge. )

Third, expand the practice.

1.

3×2 5×4 6×7

30×2 50×4 6×70

300×2 500×4 6×700

Students calculate independently and feed back the calculation results.

Teacher: What are the rules of the formula above? Tell your findings in your own words.

As long as the students speak reasonably, the teacher should give affirmation and encouragement. )

The purpose of the design is to let students express themselves in their own language, and to cultivate students' language expression ability and ability to discover mathematical laws. )

2. Guide students to talk about how to calculate the whole ten, whole hundred and whole thousand times of a number orally.

3. Math games.

The teacher prepares cards in advance and plays games at the same table.

Rules of the game: One student takes a number, the other student takes an integer of ten, one hundred or one thousand, and then both students calculate the multiplication result of these two numbers to see who can calculate quickly and accurately.

Tisso

Teaching objectives:

1. Knowledge and skills: According to the specific situation, explore and master the oral calculation method of multiplying integer ten, integer hundred and integer thousand by one digit, and calculate it correctly.

2. Mathematical thinking: Through the learning process of careful observation and independent thinking, develop the ability to generalize and solve problems: be able to use what you have learned to solve simple problems in life and feel the role of mathematics in life.

3. Emotional attitude: experience the process of learning mathematics such as observation, thinking and induction, and feel the rationality of the mathematical thinking process.

Teaching focus:

Can correctly calculate the whole ten, whole hundred and whole thousand times of a digit.

Teaching rules:

According to the teaching content and students' thinking characteristics, the basic idea of the new curriculum standard is to let students "learn mathematics that is valuable to everyone". It is emphasized that "teaching should start from students' existing experience and let students experience the process of abstracting practical problems into mathematical models and explaining and applying them". In order to achieve the teaching goal, effectively highlight the teaching focus and break through the difficulties, according to the theory of modern cognitive science, I mainly adopt the following teaching methods and learning methods.

In teaching, I mainly use the method of creating scenes to stimulate students' interest in learning and motivation for positive thinking. Teachers speak well and students practice much, which embodies the teaching principle of students as the main body and teachers as the leading factor.

Teaching and learning learn from each other. I mainly adopt the learning methods of independent inquiry and cooperative communication. Hands-on operation, independent exploration and cooperative communication are important ways for students to learn mathematics. Following the law of students' cognitive thinking can fully mobilize students' initiative and enthusiasm, give students more space for exploratory learning, and let students think independently in specific situations.

Teaching process:

First, create situations and ask questions.

First, show the theme map on the second page of the textbook. The school will organize tree planting activities and provide us with many small trees. Students carefully observe the pictures and ask: What mathematical information can you get from the pictures? And ask related math questions? So as to guide students to ask questions, "There are three bundles of small trees, each bundle of 20 trees. A * * *, how many small trees are there? "

Starting from the familiar situation, this link not only narrows the distance between mathematics and students, but also transforms students' existing knowledge and experience into new knowledge, making students easily accept new knowledge and cultivating students' problem consciousness.

Second, explore independently and solve problems.

I set up three activities in this conversation.

An activity

Ask the students according to the question, "There are 3 bundles of small trees, each bundle has 20 trees. A * * *, how many small trees are there? " List the formulas and try to calculate them.

Students can list the formula 20 X 3 or 20+20+20 and calculate that the answer is 60 trees. Then discuss the formula "20 X 3" in the group. Let the students talk about the meaning and calculation method of this formula in the group.

The group sent representatives to speak. In the formula 20 X 3=60, 20 means there are 20 trees in each bundle, 3 means there are 3 bundles, and 60 means there are 60 small trees. Students may propose the following calculation methods.

1 and 20×3 are the addition of three 20s, and the formula is: 20+20+20 = 60;

2.20 can be regarded as two 10, so 20×3 can be changed into six 10, which is 60.

3、2×3=6,20×3=60

Don't look at the "0" after 20, 2×3=6, and add a "0" after 6 after multiplication, which is equal to 60.

Contrast algorithm: Which of the above algorithms do you think is simpler?

After learning the meaning of multiplication, students will rule out addition according to their existing experience and naturally choose the third method. The third method is the oral calculation method that students want to master in this class, so we should seize the opportunity to summarize and strengthen it in time: in the multiplication formula of integer ten digits, don't look at the "0" at the end of the multiplier first, and then add the same number of "0" at the end of the product after multiplication.

Teachers and students complete the questions together, and teachers will demonstrate writing on the blackboard to help students develop good writing habits.

After solving the problem, continue to add the question: How many small trees are there in 4 bundles? How about five bundles?

Using the newly optimized oral calculation method, students can complete the questions independently and further strengthen the oral calculation method.

Activity 2

After students have mastered the oral calculation method of multiplying an integer by a digit, they independently complete the second question of "Try it" on page 2 of the textbook.

Students get the results of the formula through independent calculation, guide students to observe and compare these groups of questions, find out the rules of the vertical formula, and express their findings in their own words. Students can find that if one multiplier is constant, there will be one more "0" at the end of the other multiplier and one more "0" at the end of the product. The students moved the method of multiplying an integer by a digit to the method of multiplying an integer by a digit. At this time, strengthen the methods and let students summarize the calculation methods in their own language, which not only trains students' thinking, but also develops students' language.

Activity 3

After summing up the oral calculation methods of multiplying whole ten, whole hundred and whole thousand by one digit, the students completed the third question of "Try it".

In the process of calculation, students can quote scenes in life to explain the meaning of the formula, and students are reasonable.

While understanding arithmetic, strengthen the method of oral calculation.

Through careful observation, independent inquiry, cooperative communication and comparative discovery, students can master the new knowledge more firmly.

Third, consolidate practice and deepen new knowledge.

In this session, I will practice in three levels.

1, basic exercise

Complete the second question on the third page of the textbook.

In this exercise, students are required to calculate and consolidate the core knowledge by oral calculation.

2, improve the practice

Complete questions 1 and 3 in Practice.

Ask the students to look at the pictures independently and understand the meaning of the questions.

Through this exercise, students can apply what they have learned to life practice.

3. Divergent exercises

Work together at the same table to finish the math game on page three.

Choose three cards in the picture and spell the correct formula for integer multiplication.

Students can consolidate their oral calculation methods while playing games, and they can spread their thinking.

The three-level exercise in this link is based on students' cognitive rules and follows the principle of easy to difficult, which embodies the concept that mathematics learning serves life, not only summarizes students' thinking, but also improves students' learning ability.

Fourth, summarize the evaluation, and summarize the whole class.

Review this lesson and evaluate yourself: What have you learned? Is learning interesting? Do you have any questions?

The above teaching process design is based on students' learning psychology and knowledge starting point. By guiding students to try, actively explore and reasonably induce, students can learn new knowledge and experience the formation process of mathematical knowledge. This kind of teaching will activate students' mathematical thinking more effectively, and make students develop their knowledge, ability and emotional attitude effectively.

How many decimal trees are there?

There are three bundles of young trees, each with 20 trees. How many small trees are there in a * * *?

20 X 3=60 (tree)

1, 1, 20×3 is the sum of three twenties, that is, the formula: 20+20+20 = 60;

2.20 can be regarded as two 10, so 20×3 can be changed into six 10, which is 60.

3、2×3=6,20×3=60

A * * * has 60 small trees.