Teaching content of "Decimal Multiplying Integer" teaching design: Page P2-3, Unit 1, Book 9, People's Education Press, Example 1, Example 2.
Teaching objectives:
1. experienced the process of converting decimal multiplication into integer multiplication, and realized the conversion method.
2. Understand the arithmetic of multiplying decimal by integer, master the general method of multiplying decimal by integer, and you will do the written calculation correctly.
3. Feel the wide application of fractional multiplication in life.
Teaching emphasis: understand the operation of decimal multiplication by integer and master the algorithm.
Teaching difficulties: realize that decimal times integer can be converted into integer times integer, explore and use it? How many decimal places is the factor and the product? Law.
Prepare teaching tools: courseware and homework paper.
Teaching presupposition:
First, the scene import, stimulate interest
On Children's Day, kindergarten children need sun hats for their performances. The teacher learned the price of the sun hat (as follows).
Second, actively participate in and experience the process.
(1) Decimal times integer.
One sun hat for 3.5 yuan, 3 for a pack. How much is this parcel?
1, students orally list the formula: 3.5? 3。
2. Calculation results.
(1) Students think independently and write their ideas on paper.
★ The teacher goes to each group of students 1 to guide the calculation.
(2) After each student has an idea, the group exchanges the calculation process.
★ The team leader collects everyone's ideas and arranges students with different ideas to talk; Instruct the students 1 to talk about it.
◆ Students with difficulties, with the help of wisdom keys: ① use decimal addition calculation; (2) With the help of unit reciprocity, the decimal is converted into an integer for calculation; ③ Divide the decimal into integer parts and decimal parts for oral calculation; (4) Using vertical calculation results; ⑤ Use the transformation method you think of to express the correct calculation result.
3, teachers patrol, pay attention to communication within the group, find a report team.
Default calculation: ① 3.5+3.5+3.5; ②3.5 yuan = 35 angle, 35? 3; ③3? 3,0.5? 3; ④ Vertical representation, integer form; ⑤ Vertical representation, decimal form; ⑥ Other forms
4, reporting, the teacher's main breakthrough: written calculation teaching◆ In the reporting process, the teacher mastered the first few forms of reporting, and then focused on explaining the calculation process of decimal written calculation.
Write on the blackboard: 5. Say it.
(1) Please 1 give a demonstration to two people.
(2) In the group, the group leader leads everyone to talk.
(3) Ask students 1 to have a collective dialogue.
(2) Decimal times two-digit integer
Now, the kindergarten teacher decided to buy a hat like 12.
Title: One sun hat, 3.5 yuan, 3 tops in a pack. How much does it cost to buy a hat like 12?
1. List the formula: 10.5? 4 3.5? 12
2. Independent vertical calculation
(1) Most students did it independently.
(2) No.65438 +0 students and teachers * * * completed vertical calculation (pay attention to the writing format and calculation reasons).
(3) Ask a student to write 10.5 on the blackboard? 4. Let's talk about arithmetic.
3. Focus on 3.5? Vertical calculation of 12
(1) Collect wrong questions, show them and correct them.
(2) Correct vertical writing. (Decimal processing; Processing of the last bit 0)
(3) Students who make mistakes in calculation modify their own calculations.
Step 4 Ask questions in class
(3) Reveal the topic
1, fractional multiplication
2, the calculation method of induction
Third, apply new knowledge to solve problems? Decimal times integer? Teaching Reflection This lesson is the first lesson of multiplying decimal by integer, which is mainly to let students understand the meaning of multiplying decimal by integer, master the calculation rules of multiplying decimal by integer, and cultivate students' ability to acquire new knowledge actively. In order to make it easy for students to master new knowledge, I tried to do the following:
1. Review the significance of integer multiplication and the law of product change caused by factor change in integer multiplication for students to learn? Decimal times integer? I have made good preparations, especially mastering the changing law of product, which is of great help to learn the arithmetic of multiplying decimal by integer.
Second, created a? Buy a kite? Situation, thus stimulating students' interest in learning. When solving practical problems, it naturally leads to the learning content of multiplying decimals by integers, which makes students feel cordial and natural, and students explore new knowledge with strong interest.
Third, in the process of learning, I pay attention to students' independent thinking. For example, when solving practical problems, I ask students to think about communication solutions together. In the communication between teachers and students, students can fully express their views and calculation methods, so as to get many creative solutions. Then under the guidance of the teacher's inspiration, help students better understand the arithmetic and method of decimal multiplication of integers.
In short, this course pays more attention to students' learning process. In the study of thinking and communication, different students are given space to develop their thinking and promote their development.
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