Examples and exercises of "Thinking and Doing" on pages 48~50 of Mathematics, the standard experimental textbook of compulsory education curriculum in Jiangsu Education Press.

Second, a brief analysis of teaching materials:

This part of the teaching content is two-digit plus one-digit oral calculation that needs to be carried. Examples focus on children's pictures. First, it teaches that sum is an integer of ten with two digits plus one digit, focusing on the carry principle. Teach two-digit plus one-digit and non-integer decimal carry addition again, and advocate diversification of calculation methods. "Try it" allows students to learn one digit plus two digits on the basis of examples. "Thinking while doing" helps students master the calculation method first, and then guides them to solve some practical problems.

Third, the teaching objectives:

1. Let students experience and explore the calculation process of adding two digits to one digit (carry) and develop problem-solving strategies. Can understand the arithmetic of two digits plus one digit (carry), master its calculation method, and can calculate correctly.

2. Cultivate students' hands-on operation, language expression and problem-solving ability.

3. Cultivate students' spirit of independent exploration and good study habits.

Fourth, the teaching process:

(A), the review of bedding

1. Look at this card.

①4+6=( ) 4+9=( )

②20+ 13=( ) 30+3=( )

③5+9+30=( ) 8+2+40=( )

2. Say the name and process of oral calculation.

① How to calculate 24+2 = ()?

Comments: The review is highly targeted and pays attention to the internal connection between knowledge. The oral calculation of the first question is the basis of learning new knowledge, and it is also the connection point of old and new knowledge, which clears the way for learning new knowledge. The second problem is to review the oral calculation method of adding two digits to one digit (not carrying), so as to prepare for learning new knowledge and help students migrate the calculation method. This not only attaches importance to the memory of knowledge, but also attaches importance to the transfer of methods.

Second, create situations, ask questions and introduce new knowledge.

1. The courseware shows the situation diagram in the textbook. After introducing their names, three cartoon characters guide students to observe and think: What are the children doing in the picture? What did they say? What else do you want to know from their conversation? May I ask the question of addition calculation?

2. The teacher writes the questions raised by the students and the corresponding formulas on the blackboard (omitted). Narrator: The children asked so many questions. Today, let's solve these two problems first.

(1) How many Zhang Xiaoming and Xiao Hongyi * * *? 24+6 = () ② How many tickets do Xiaoming and Xiaojun have? 24+9=( )

Third, explore new knowledge and explore problems.

(1) "Xiao Ming and Xiao Hong Yi * * *, how many pieces? 24+6=( )

1. Let the students discuss what is important first.

2. Question: First calculate 4+6 = 10. What should we do next? Can you swing it with a stick?

3. After students learn to operate tools, they will communicate with each other in class and talk about how to calculate.

4. The teacher arranges the blackboard books according to the students' ideas:

5. Discuss in groups: What are the similarities of "24+2" algorithm in the initial review of "24+6"? What is the difference?

6. Communication summary: What if the figures add up to get 10?

Comments: The teacher did not instill the algorithm into the students, but gave full play to the transfer function of two-digit plus one-digit (no carry) oral calculation, and asked the students to calculate 4+6 = 10 first, and found that the number was 10. When there was a contradiction with the original understanding, they explored the algorithm with a stick and initially realized the arithmetic. search problem

(2) Xiao Ming and Xiao Jun * * * How many pieces, 24+9 = ()

1. Students put a pendulum with a stick and explore the algorithm of 24+9.

2. Operation flow of group communication.

3. Communicate in large groups. Encourage students to show different postures.

4. Pattern combination to further understand arithmetic.

5. Compare and choose your favorite algorithm.

6. Summary: What if the sum of digits exceeds 10? Who is used to adding up the whole ten?

Comments: Let students give full play to the stick, talk about the process, use their brains, do things, speak freely, explore independently, and cooperate and communicate, which not only cultivates students' hands-on operation, language expression and thinking ability, but also cultivates students' exploration spirit and realizes the diversity of problem-solving strategies.

7. Try it: How do you want to calculate it? 8+24= mouth 5+39 = mouth

(1) How do students communicate with their deskmates after independent calculation?

② Question summary: Two digits plus one digit, no matter whether the first addend is one digit or two digits, which digits should be added first? What if the figures add up to 10?

Fourth, consolidate the application

1. Think about it and do it 1: Circle and calculate.

(1) Everyone in the class used their brains and made a calculation.

(2) How is communication circled and why?

2. "Think and act" question 2.

(1) grouping calculation.

(2) Comparison: What are the top four questions in the same group? Let the students further clarify their reasoning.

3. "Think and act" question 3. Let the students read the conditions, find out the meaning of the problem and solve it independently.

4. "Think and act" question 4.

(1) Guide the students to look at the pictures carefully: What is the price of each item? What did the three children buy? Say and say, "How much should everyone pay?" What do you mean?

(2) After the students calculate in the form of columns, instruct the students to answer the solved questions in three sentences respectively.

5. Open question: How much can I fill in the following mouth? More than 25 ports = 3 ports

The teaching of verbs (abbreviation of verb) is over;

General comments:

This lesson embodies the concept and requirements of the new curriculum standard in the determination of teaching objectives. Teachers' teaching concept is new, and they put the cultivation of students' ability to solve problems and explore independently in the first place, paying special attention to giving full play to students' main role and changing students' learning methods. In terms of teaching methods, teachers can make use of the transfer of knowledge and methods to make students start work, use their mouths and brains, and explore, discover and solve new problems by themselves, which truly embodies the teaching concept of teachers taking students' development as the center.

In the process of students' independent exploration, students discuss, cooperate and communicate in groups, and everyone expresses his own views and ideas, which not only cultivates students' oral expression ability, but also develops their thinking ability and problem-solving ability. The design of open questions not only consolidates new knowledge, but also stimulates students' desire for further exploration and discovery.