Teaching material analysis.

"Two plus one (carry plus)" is located in the next issue of the first grade primary school mathematics textbook published by Xi Shi Normal University.

Unit 6 Addition and subtraction within 100 (2) This unit is one of the key contents of the whole textbook, and it is an important basis for learning carry addition and elementary arithmetic within 10,000 in the future.

The content of this lesson is based on the children's mastery of "carry addition within 20" and "carry addition within 100". Two digits plus one digit (carry plus) not only pays attention to oral calculation, but also continues to introduce vertical calculation, which embodies the diversification of calculation methods and methods.

Second, students.

Children in Grade One and Grade Two have been able to calculate the carry addition within 20 skillfully, and can calculate the carry addition within 100 in many ways, and can write correctly and calculate vertically.

The children in this class are curious about things related to mathematics around them, can collect mathematical information and ask mathematical questions, can actively participate in mathematical activities such as operation and observation, and have good study habits.

Third, talk about teaching objectives.

1, let students go through the process of exploring the calculation method of adding two digits to one digit (carry) and make correct calculations.

2. Cultivate students' innovative consciousness in observation, train students' thinking flexibility, cultivate students' independent inquiry ability in operation, discussion and communication, and obtain diversified algorithms.

3. In solving practical problems, further experience the connection between mathematics and life, enhance mathematical consciousness, stimulate mathematical interest and develop mathematical thinking.

Fourth, talk about the difficulties in teaching.

Key points: make students master the calculation method of two-digit plus one-digit (carry), improve the calculation speed of students and cultivate their ability to solve practical problems.

Difficulties: Understand the carry principle and improve the calculation ability.

Verb (abbreviation for verb) Speaking and teaching methods

Curriculum standards point out that mathematics teaching is the teaching of mathematics activities, and the role of teachers in teaching activities is to organize discovery activities, pay attention to students in activities, and let students learn new knowledge and experience the exploration process in exploration.

Situational teaching method, operation experiment method and discovery method have become the teaching methods and means adopted in this course.

Six, said the learning method

In mathematics learning, first-grade children prefer vivid and interesting learning situations, vivid and intuitive operations and colorful games to attract their attention and stimulate their enthusiasm for learning activities. In this class, children actively participate in the process of acquiring knowledge through operating exercises, observation and analysis, cooperative inquiry and other learning methods.

Seven, talk about the teaching process.

Bruner, a famous American psychologist, believes that "the best stimulus for learning is interest in the materials learned." This argument tells us that in teaching, we should fully tap the incentive factors of the textbook itself, let children know the close relationship between mathematics and real life, and feel the value of mathematics in life, thus stimulating children's desire and motivation to learn mathematics.

First, create a situation to stimulate interest

1, show the scene diagram.

The scene diagram of the example 1 in the textbook is a scene of taking children to play and then taking them to pick apples. I think the advantage of this approach is that children can review old knowledge naturally in the scene. Then ask the students to say 24+3. How did you work it out? Then ask the students to observe the pictures of two children preparing mineral water on the playground. Ask the students questions and try to calculate. Ask the children if 24+9 equals 33? Let's learn the carry addition of two digits plus one digit. I believe that after you have studied it, you will soon be able to work out what 24+9 is. Then the topic of writing on the blackboard leads to new knowledge. This design not only paves the way for today's study, but also stimulates children's interest in learning and thirst for knowledge.

The thinking of first-grade children is mainly in concrete images, and the teaching difficulty of this course is "from ten to ten", which is the contradiction between the abstract generality of this mathematical knowledge and the concrete images of students' thinking. An important role of teaching methods is to concretize abstract knowledge, so that children can better understand mathematical knowledge in vivid and concrete situations and in the activities of operation, practice, observation and analysis.

Children, do you want to go to the playground? (Thinking) Then come with me. Look, this is a playground. There is a magic wheel, a seesaw park and a boating park. Hey, what are a group of children doing under the tree? Let's go and have a look. It turns out that there are big and red apples hanging on the tree. Do you want to pick it? (Thinking) Okay. Pick this apple first. Teacher: Right? The whole class will come. Great! (right)

Who can tell the teacher how to calculate 24+3? (4+3 = 7, 7 plus 20 equals 27) Is that right? (Yes) Great! On the playground, two children are preparing mineral water for everyone.

There are 24 bottles of mineral water in the box, and 9 bottles have been bought. Who can ask a math question? How many bottles of mineral water are there? ) very good! Who can make the formula? (24+9 = 33) What do you mean? (33) Does 24+9 equal 33? Today, we will learn the carry addition of two digits plus one digit. I believe that after learning, we can quickly work out how much 24+9 equals? Do you have confidence? (Yes)

Second, explore the algorithm in operation practice

In this section, I arranged three teaching activities to break through the difficulties of this class.

1, swing lever

There are 24 sticks on the left and 9 sticks on the right. Can you calculate this number with a stick?

The child has encountered a new problem. The number of 24+9 adds up to 10. How to deal with it? Then exchange the method of throwing sticks at the same table.

Then let the children talk about their own swing.

In this activity, children may have some ways to put sticks.

(1) First combine 4 and 9 to make 13, take out 10 from 13 to bind, and 20 and 13 will make 33.

Display algorithm

24 + 9=33

20 4

13

(2) Take 6 out of 9, put them into 4, and bundle them into a bundle. 20 plus 10, plus 3 equals 33.

Display algorithm

24 + 9=33

6 3

30

(3) Divide 24 into 23 and 1, 1 and 9 to form ten.

Display algorithm

24 + 9=33

23 1

10

The children solved the new problems they encountered by putting sticks to explore independently, and constructed the meaning of mathematical knowledge. Then they shared the joy of learning success in the process of cooperation and exchange, and the initiative and enthusiasm of learning were fully exerted. Let the boring calculation learning become lively and interesting, and the image is intuitive. )

This link provides a good opportunity for children to show and communicate, and gives full play to the advantages of multimedia-assisted teaching in time and speed. Let the classroom become a platform to show the thinking process and a "gas station" for students to accumulate wealth and share resources.

I try my best to make students feel the generation and development of mathematical knowledge and let children understand and form mathematical thinking in the construction of knowledge. This mathematical thinking is the fundamental purpose of teaching.

2. Summary

All right, let's put the stick in the bag and act quickly. Students, 24 plus 9, how many algorithms did you just think of? (3 kinds)

The teacher summarized the first algorithm. Let's look at the second algorithm is to turn a few into ten (great, turn 24 into ten). The third algorithm is to turn a few into ten? (9) Which of these three algorithms do you think is faster? (Third, because ...) (I like number 1) Does anyone like number 2? (I like the second one)

Among these three algorithms, some calculate all ten first, and some make up all ten first. Why do they all have whole tens? (Because it is easy to calculate by adding up the whole ten)

3, contact with reality, solve the problem

Below, we will use our favorite methods to solve some problems.

(1) Show courseware: There are some mushrooms on the playground, 35 mushrooms on the left and 7 mushrooms on the right. Can you ask some math questions? Who can make the formula? (35+7 = 42), right? (Yes) Great! Who can tell me how you worked it out? (I divide 35 into 30 and 5) OK. Are there any other algorithms? (-) Anything else? (——) Oh, very good. Applause.

(2) Show courseware: Let's go to seesaw paradise. There are 18 people playing in the seesaw park, with 8 more people. How many people are there? Who can make a statement? (18+8 = 26), right? Give it a compliment.

(3) Show courseware: Next, let's go boating paradise. There are 9 hand boats and 56 swan boats in the boating paradise. How many ships are there? Who can make a statement? (56+9 = 65) Who can tell me how you worked it out?

Ok, children, what we learned today is on page 62 of the book. Please open your book and have a look at Example 2. Ok, please take out your pen and finish these three questions carefully. Be a good classmate, please sit up straight! Is it finished? Let's check the answer. The whole class applauded themselves. Very good!

All right, children, close the books quickly. There are more interesting places waiting for you on the playground. Do you want to go? (thinking)

Look, this is an amphibious island. Do you want to play on the island? Land and water island is fun! You must choose a good route and make a correct oral calculation before you can reach the island safely. Otherwise, you will fall into the river and hit a big shark. Are you ready? Start with 1 and read by the whole class (42+8 = 50). Correct! What number will you choose next? (No.2) Why didn't Card No.2 turn green when we read together (4+46 = 50)? It can be seen that we have been cheated. Ok, come back quickly and go on the 3 rd. What's the next number? (4th, 5th) What's the next step? (Take 6, 7, 8) How nice! 10 lawn should be filled with+or-. Guess what to fill in? (Plus sign) 56+4 = 60, and 60 is greater than 57. Congratulations! We bravely rushed to the land and water island. We went to the island to play.

Through the above exercises, let the children understand the arithmetic of two digits plus one digit, and on the basis of understanding the arithmetic, further consolidate the calculation method through calculation exercises.

Third, the class summary

Children, what did we learn today? (carry addition of two digits plus one digit) What is carry? Talk to the students.

Please observe carefully that one of 24+3 and 24+9 is equal to 29. Why is one equal to 30? (Because 4 plus 9 equals 13, rounding is greater than 10. ) Yes, 4 plus 9 equals 13. If it is more than ten, where should I carry it? (Decimal) 24+3 = 27, 4+3 = 7, 4 plus 3 is less than ten, so we don't divide one into ten. Four plus nine is already ten, so we should add one into ten.

Fourth, try independent and divergent thinking.

Friedenthal, a famous Dutch mathematics educator, said: "The only correct way to learn mathematics is to re-create." That is, children discover and create what they want to learn, and the teacher's task is to guide and help children to do this re-creation work.

Today we learned carry addition. Is it useful in life?

The teacher has 20 apples to share with you. Among them, boys 15, girls 6. Is it enough? (Not enough) Why?

It's spring now, and nature is so beautiful! Look, students, the teacher is going to take you on a spring outing, including 28 people in a big car, 9 people in a bus/kloc-0 and 3 people in a small car. How many people do the cart and the car need? (28+3 = 3 1, that is, 3 1 person) How many people does the bus and car need? (19+3 = 22,22 people)

This kind of teaching consolidated the knowledge learned today, improved children's interest in computing, and formed a classroom climax. )

In the teaching of the whole class, I didn't simply teach the calculation method to the children, but let each child actively construct, explore the algorithm process, understand the carry principle, realize the diversity of calculation methods and stimulate the children's learning enthusiasm in vivid situations according to their existing knowledge and experience.