Tisch
Teaching goal: 1, experience learning activities such as observation, measurement and guessing, and feel that decimals are born in life and exist in every corner of life;
2. Understand the meaning of decimals, be able to name all parts of decimals, master the reading and writing methods of decimals, and read and write decimals correctly;
3, in the process of cooperation and communication, feel the fun of mathematics learning.
Teaching methods:
Teaching method is the sum of a series of activities taken by teachers and students to achieve their goals in the teaching process. According to the characteristics of teaching content and students' thinking, I chose the optimal combination of trial and error method and guided discovery method. Guide them to find problems, analyze problems, solve problems and acquire knowledge, so as to achieve the purpose of training thinking and cultivating ability. The meaning of decimals belongs to concept teaching, which is abstract and concise. According to students' cognition of concepts, they generally follow the law of perception-representation-abstract generalization-forming concepts.
1, understand decimals from life and make clear the necessity of using decimals.
2. Understand and abstract the meaning of decimals from the existing life experience.
3. Through observation and measurement, let students fully feel and experience that decimals are produced in life, and let students feel that decimals are everywhere in life.
4. Understand the ubiquity and wide application of decimals in life, experience the mathematics around you, and feel the value and fun of mathematics learning.
Teaching methods:
1. Learn to observe, measure and summarize, and decimals can be found everywhere in life.
2. Guide students to explore independently and cultivate their ability to solve new problems by using existing knowledge.
3. Cultivate students' self-study ability and good cooperative communication habits by guiding independent reading and reporting exchange activities.
Teaching process:
First, create scenarios to introduce new lessons.
Create a holiday scene of "5. 1" to make the content of this lesson consistent with the students' real life experience.
1. What did you buy during the holiday? How much did it cost?
2. The teacher bought a book. Let's guess how much it is worth.
Judging from the students' answers, this number can't be expressed by integers, but only by decimals. Introduce the topic.
This design aims to connect boring mathematics knowledge with students' real life, stimulate students' interest in learning, ignite their sparks of seeking knowledge, thus entering a new learning state and gathering motivation for actively exploring new knowledge.
Second, clear goals and explore new knowledge.
Students all know that decimals exist in our lives, so what do students want to know about decimals?
First, the default student questions (default)
1, where did the decimal come from? (How did this happen?)
2. What is a decimal? (Decimal meaning)
3. How to read and write decimals?
According to the questions raised by students, teachers and students analyze the questions.
1, teachers and students sum up the meaning of decimals
(1) Decimals such as "0. 1, 0.3, 0.9" are called 1 decimal places. (The denominator is a fraction of 10, which can be written in decimal places 1. 1 Decimal places represent tenths. )
(2) Decimals like "0.0 1, 0.04, 0. 18" are called 2-digit decimals. (The denominator is a fraction of 100, which can be written as 2 decimal places. Two decimal places represent percentages. )
(3) Decimals such as "0.001,0.0 15, 0.2 19" are called 3 decimal places. (The denominator is a fraction of 1000, which can be written as 3 decimal places. Three decimal places represent thousands. )
2. Learn how to write decimals
Third, consolidate new knowledge.
1, practice "testing you"; (Practice) Question 1
2. Measure the height of the deskmate in meters;
3, vegetable market to buy food statistics.
Combining the application of decimals in real life, let students experience teaching and feel the fun of mathematics learning.
Four. abstract
1 to understand the history of decimals. (small message)
Understand the history of decimals and inspire students' patriotic enthusiasm.
2. After taking the decimal course, can you tell me what you know?
Verb (abbreviation for verb) assignment
1, record some decimals from life and communicate with each other tomorrow;
2. Complete the "exercise book"
Arrange practical homework, let students combine the application of decimals in real life, experience teaching at hand and feel the fun of mathematics learning.
extreme
Teaching objectives:
1, understand the meaning of decimals, and know that one decimal, two decimals and three decimals represent several tenths, several percent and several thousandths respectively. ...
2. Know that the progressive rate between the counting unit on each bit and two adjacent counting units is ten, and get a preliminary understanding of how many such units there are in each bit of a decimal part.
3. By understanding the generation and development process of decimals, we can improve our interest in mathematics learning and enhance our love for mathematics.
Teaching focus:
Understand the meaning of decimal.
Teaching difficulties:
The result of unit of measurement conversion is expressed in decimal.
Teaching preparation:
Multimedia courseware, meter ruler.
Teaching process:
First, introduce new grants.
Teacher: Where have you seen decimals in your life? Can you talk about it? (Show the courseware) Students answer.
Teacher: Decimals are used in so many places in life, which shows that decimals are widely used and everywhere. Please talk about the data of measuring the length, width (or height) of the surrounding objects. The teacher will divide the data into "whole meter number" and "non-whole meter number" on the blackboard. )
Teacher: If you still want to write these parts in meters, what numbers can you use besides scores? Please read the content on page 32 of the textbook.
Teachers and students have the same induction: when measuring and calculating, it is often impossible to get integer results, so it is often expressed in decimals. But what is the meaning of decimals? In this lesson, we continue to learn more about decimals.
Blackboard writing: the meaning of decimals.
Second, exploration and discovery.
1, know a decimal place.
(1) courseware shows an example of 1 meter scale on page 32 of the textbook.
Divide 1m into 10 parts. How long is each part? 1 decimeter?
The teacher introduced and demonstrated that "one tenth" meter can also be written as 0. 1 meter.
What about 2 decimetres and 3 decimetres? Students try to fill in the blanks.
Students communicate in groups, and then the whole class communicates. When communicating, talk about the meaning of each score.
The teacher writes on the blackboard according to the students' answers.
1 decimeter = meaning and nature of decimals in Unit 4 of PEP Mathematics for four years (1) m =0. 1 m, 3 decimeters = meaning and nature of decimals in Unit 4 of PEP Mathematics for four years (1) m = 0.3m. ...
(2) Observing the above equation, can you find the connection between fractions and decimals?
Students observe and discuss in groups.
Summary after communication between teachers and students: the denominator is 10, which can be written as a decimal. A decimal place represents a few tenths.
2. Know two or three decimal places.
We know that one digit after the decimal point represents a few tenths of a number, so what should two or three digits after the decimal point represent? Now, please take these two decimal places as materials and continue your research.
(1) The teacher continued to show the enlarged view of the meter ruler.
Students give feedback after thinking and group communication.
Divide 1 meter into 100 parts, and one or more parts of the meter represent a few percent, which can be expressed by two decimal places such as 0. 04 and 0.0 1.
1 meter has 1000 mm, that is to say, 1 meter is divided into 1000 copies on average, and 1 mm is the meaning and nature of the fourth unit decimal in the four-year (1) meter of mathematics published by New People's Education Press, which is 0.000 in decimal terms.
(2) summary.
The denominator is a fraction of 100, which can be written as two decimal places. Two decimal places represent a few percent.
The denominator is a fraction of 1000, which can be written as three decimal places. Three decimal places represent thousands.
3. The meaning of decimals.
The denominator is 10, 100, 1000 ... Such a score can be expressed in decimal. What are the units of these decimals? What is the forward speed between every two adjacent counting units?
Students talk about their understanding of decimals
Teachers and students * * * come to the conclusion that a decimal place means a few tenths, and the counting unit of a few tenths is one tenth, so the counting unit of a decimal place is 0. 1. Similarly, the counting unit of two decimal places and three decimal places is 0. 0 1 and 0.005438+0. The propulsion rate between every two adjacent counting units is 10.
4. Read "Do you know?" .
Teacher: Students already know how decimals are produced and what decimals mean. Do you know the history of decimals?
Page 33 of the self-study textbook for students "Do you know?" .
When communicating with teachers and students, let students talk about the development history of decimals.
Third, consolidate differences.
1. Guide students to complete the "doing" on page 33 of the textbook.
Let the students fill in independently, and when correcting collectively, let the students talk about how to express it with fractions and decimals.
2. Fill in the appropriate decimal places in the brackets.
The Significance and Nature of Decimals in Unit 4 of Four-year Mathematics of People's Education Press (1)
() Yuan () kg () cm
Fourth, evaluation feedback.
What did you learn from today's class?
Summary after communication between teachers and students: Knowing decimals, I know decimals are used to represent numbers of one tenth, one hundredth and one thousandth. I also know the counting unit of decimals, and I know that the progressive rate between adjacent counting units is 10.
Blackboard design:
The meaning of decimal
Fractions with denominators of 10, 100, 1000 ... can be expressed in decimals.
Decimals are counted in tenths, hundredths and thousandths ... Write 0. 1, 0.0 1, 0.00 1 ...
The propulsion rate between every two adjacent counting units is 10.
Tisso
Teaching objectives:
1. Knowledge and skills: through observation, operation and other activities, combined with specific conditions, master the reading and writing methods of decimals and understand the meaning of decimals.
2. Process and method: Experience the process of exploring the meaning of decimals and understand the wide application of decimals in life.
3. Emotional goal: to experience the fun of mathematics learning in the process of exploration and communication.
Teaching focus:
Understand the meaning of decimal.
Teaching aid preparation:
Rectangular and square pictures, multimedia courseware, etc.
Teaching rules:
According to the curriculum standards and teaching materials, I will adopt heuristic teaching methods to guide students to actively observe, experiment, guess, verify, reason and communicate.
Teaching methods:
Hands-on practice, independent exploration and cooperative communication have become the main ways of students' learning, which has promoted students' personality development and ability improvement.
Teaching process:
In order to achieve the above goals, highlight key points and break through difficulties, I have designed the following five teaching links.
First, create situations and provide materials.
This link is divided into two steps. The first step is to observe the situation and read and write decimals.
Show the information window, guide the students to observe and ask questions: What mathematical information do you know from the pictures? Look at the pictures and tell the quality of various eggs. Then ask: How to read and write these decimals? Students try to read and write decimals. Teachers always modify the way students read and write decimals. Because the students have learned how to read and write with one decimal place, there is no need to explain too much here. Let the students summarize the reading and writing methods of decimals in the reading and writing process and complete the transfer of knowledge.
The second step is to ask questions according to the information.
Question: Based on this information, what questions can you ask? Students may ask: What does 0.25 in 0.25 Jin mean? What does 0.365 in 0.365 Jin mean? The design intention of this link is to create question situations and stimulate students' interest in asking questions.
Second, analyze materials and understand concepts.
This link is divided into two steps. The first step is to understand the meaning of two decimal places.
This step is divided into four small links, 1 small link. First, guide students to choose the problems that need to be solved. To understand what 0.25 means, we must first understand what 0.0 1 means. (blackboard 0.25 0.0 1)
In the second small link, show a square piece of paper and ask: If the square piece of paper is represented by "1", then it is divided into 10 pieces on average. How does each work behave? If divided into 100 shares on average. How to express each copy?
Let students answer first. Students should know the relationship between 0. 1 and110, and then let students slowly transition to the relationship between 0.0 1 and1/00.
(Teacher's blackboard: 0.1-110 0.01-100)
0.25 is displayed on a square piece of paper.
Question: We know that 0.0 1 is1100, so can you express 0.25 on this square paper? What does this mean?
Let the students discuss in groups first, then cooperate in groups and communicate with the whole class.
Teachers guide students to make it clear that 0.25 is 25/ 100, which means 251100.
Blackboard writing: 0.25 25/ 100
The third small link, multimedia shows the grid diagram of 0.05 and 0. 10. What does the shaded part mean? Blackboard: 0.055/1000.1010/00.
The fourth small link, group discussion: What are the characteristics of these decimals?
Let the students communicate in groups, let different students express their ideas, and then communicate with the whole class.
Guide the students to summarize the meaning of two decimal places.
Students already know the meaning of decimals. By reviewing the meaning of one decimal, we can learn the meaning of two decimals, so that students can connect their mathematical knowledge in series when exploring new knowledge. The second step is to understand the meaning of the three decimal places.
This step is divided into four small steps. The first step is to ask: We already know the meaning of the two decimal places. Guess: What does 0.00 1 mean? What does 0.365 mean?
Ask the students to answer directly. Inspired by two decimal places, students can naturally move to three decimal places.
In the second step, the teacher showed the process of the dynamic average score of 0.365 for the large cube plastic block through multimedia, and guided the students to understand that 0.365 is 36511000, which is 365/ 1000.
Step 3, multimedia display 0.305 and 0.360 shadow block diagrams. What does the shaded part mean? Please look at the block diagram of multimedia and count it.
The fourth step is to guide students to summarize the meaning of the three decimal places.
After reviewing the meaning of one decimal place and learning the meaning of two decimal places, students can explore and discover the meaning of three decimal places by themselves through self-study, which is conducive to the development of students' induction and inquiry ability.
Third, with the help of materials, summarize the concepts.
Question: Today we know decimals, such as 0.25 and 0.365. Have you ever seen such a decimal in your life?
Students look for decimals in life and tell their meanings in combination with reality. Collective communication, teachers guide students to summarize the meaning of decimals. Therefore, we know that numbers such as 0. 1 and 0.25 0.365 representing one tenth, one hundredth and one thousandth are called decimals. (and show the topic: the meaning of decimals. )
The design intention is to make students accumulate rich perceptual knowledge, lay a solid foundation for students to abstract and summarize the meaning of decimals smoothly, and feel the universality of decimals in life through observing, coloring and operating square pieces of paper and cubic plastic blocks, as well as students' search and understanding of decimals in daily life. The fourth link is to consolidate, expand and apply concepts.
I designed two levels of exercises. The first one is "independent practice 1", which is to practice the relationship between decimals, further understand the meaning of decimals, and understand students' understanding of the meaning of decimals by completing the exercises.
The second is Independent Exercise 2. With the help of learning tools, let students consolidate the meaning of decimals, express the meaning of each decimal in different ways, and pay attention to students' mastery of the meaning of decimals.
Design Intention The purpose of designing independent exercises is to enable students to consolidate what they have learned today, arrange exercises appropriately for newly learned knowledge points, and test the effect of students' study in class.
Fourth, class summary.
Dialogue: Today we learned more about decimals. What have you gained? Can you share it with us?
[Design Intention] Let students share the joy of learning success, stimulate students' enthusiasm and curiosity, and sum up experiences and methods for students' follow-up study.
Intuitive and simple, suitable for the whole class to complete.
Practice by yourself 12
This is a question of thinking, and the practical application of learning knowledge today can let interested students practice it.