1, understand the process of decimals, and understand and master the meaning of decimals.
2. Experience the process of decimal discovery and cognition, perceive the close relationship between knowledge and life and knowledge, and experience the learning methods of inquiry discovery and transfer reasoning.
3. Understand the generation process of mathematical knowledge, be educated by historical materialism, stimulate learning interest, and cultivate learning habits of hands-on practice and cooperative inquiry.
Teaching emphasis and difficulty: understanding and mastering the meaning of decimals.
Teaching courseware: multimedia courseware. Meter ruler.
Teaching process:
First reveal the topic: the meaning of decimals.
Second, the learning goal: 1, understand the generation process of decimals, and understand and master the meaning of decimals.
2. Experience the discovery and understanding of decimals, perceive the close relationship between knowledge and life and knowledge, and experience the learning methods of inquiry discovery and transfer reasoning.
Three, self-study guidance (a): thinking preview before class:
Where do you see or use decimals? Give examples.
Under what circumstances are decimals produced?
Health: In view of the above two questions, talk about understanding and exchanging feelings.
Teacher: Show me the meter ruler and ask a classmate to measure the length of the blackboard. How many meters is rice?
Clear explanation: when measuring, you can't get an integer result, so you usually use decimals to express it.
So what does decimal mean?
Fourth, learn first.
1, self-study guide (2): Know a decimal place.
Read 50 pages by yourself and think:
Divide 1m into () parts, each part is () decimeter, expressed as () meter by fraction, or written as () meter by decimal.
How much are these three copies? How many meters is rice? How about seven servings like this?
2. Report after reflection.
3. Teacher: How did you get these decimals?
Five, after-school teaching:
Clear: divide 1 meter into 10 parts on average, which means that one or several parts are one tenth or several tenths, and the decimal is 0. 1 or 0.0.
Division; These decimals have only one decimal place after the decimal point, so we call such decimals decimal places. What do decimal places like this mean? (Make it clear that one decimal place represents a few tenths)
Six, know two decimal places, (the method is the same as above)
Seven, know three decimal places. (The method is the same as above)
Teacher: Divide the average 1m into 10, and know a decimal. How many parts can the average 1m be divided into to measure more accurately? (100 copies) So what new knowledge and discoveries will you have?
Students think, discuss, study and report their conclusions in groups.
I see. Divide 1 m into 100 parts, each part is 1 cm,1100 m, 0.0 1 m, and two parts are 2 cm, 2/100. If there are two decimal places after the decimal point, it is called two decimal places, and the two decimal places represent a few percent.
Divide 1 m into 1000 parts, each part is 1 mm,11000 m, 0.00 1 m, and two parts are 2 mm and 2/1m.
Eight. Extension:
Teacher: If we continue to divide 1m into 10000 shares and 100000 shares, that is to say, such 1 shares are 0.000 1m and 0.000 1m-
Nine, summarize the meaning of decimal:
Teacher: Looking back at the cognitive learning just now, what is the decimal? What does this mean?
Clear: Decimal means to divide 1 meter into 10, 100 and 1000. Numbers representing such one or more parts can be expressed in decimals, with one decimal place representing a few tenths, two decimal places representing a few percent and three decimal places representing a few thousandths.
Ten, classroom exercises, using feedback:
A) Tell the meaning of the following decimals:
0.3 yuan 0.45 m 0.089 kg
B) 7 cm = () decimeter = () meter 56 g = () kilogram
C) Two people share a piece of cake, and each person gets () piece?
Class summary: What knowledge have you gained?
Twelve. Assignment: ellipsis.
Thirteen, blackboard design:
The meaning of decimal
1 decimeter110m0.1meter, with one decimal place.
6 decimeters 6&; ......& gt& gt
Question 2: The meaning of decimals 3. Teaching design? Understanding decimal-decimal counting unit and numerical sequence table (lesson 2) Understanding decimal-decimal counting unit and numerical sequence table (lesson 2) Teaching content: Examples 3 and 4 of p.30~3 1 and corresponding attempts and exercises, and complete the sixth to 10 of Exercise 5. Teaching goal: 650. 2. In the process of feeling, experiencing and exploring ...? Common units of measurement-generation measurement, length unit and area unit-generation measurement, length unit and area unit. Teaching objectives 1. Make students understand the generation of measurement and deepen their understanding of the importance of measurement; Further master the commonly used units of length and area and the rate of advancement between units, so as to systematize the knowledge learned. The generation of commonly used units of measurement, the generation of commonly used units of measurement, length units and area units in teaching plans, and the teaching objectives of length units and area units in teaching plans are 1. Make students understand the generation of measurement and deepen their understanding of the importance of measurement; Further master the commonly used units of length and area and the rate of advancement between units, so as to systematize the knowledge learned. 2. Cultivate students' ability to query and collect information online and apply what they have learned .....? Teaching Design of Counting Unit, Numeric Order and Composition of Decimals Teaching Objective: Through practice, students can understand the meaning of decimals, master the counting unit, numerical order and composition of decimals, and be proficient in reading and writing decimals. The teaching goal of the teaching design of the understanding and counting unit of large numbers: knowledge and skills: 1, so that students can know that there are more than 10 thousand numbers in life; 2. Let students further understand the counting units such as ten thousand, one hundred thousand, one million, ten million and one hundred million, and know the series, digits, process and method of numbers. Let students experience the process of revealing the relationship between counting units, and master the commonly used units of measurement-generation measurement, length unit and area unit.
Question 3: Why is the meaning of decimals the focus and difficulty in teaching? Because when children start school,
Always put numbers, addition and subtraction, etc.
I only met the knowledge of decimals.
It's hard to understand its meaning.
I don't know what the decimal is.
Then meaning needs to be the focus.
Question 4: What is the meaning of decimal point 2.5?
The sum of two 1 and five 0. 1 2.5 has two 1 and five 0. 1.
Question 5: The meaning and nature of decimals are the contents of several grades in People's Education Press. Instructional design of the meaning and nature of decimals.
Teaching content: the meaning and nature of decimals, the fourth grade of primary school mathematics.
Teaching objectives:
1, understand and master the nature of decimals;
2. Being able to simplify and rewrite decimals by using their properties;
3. Cultivate students' ability to summarize, analyze, synthesize and flexibly use what they have learned.
Key points of teaching materials: Through exploration, we can find the nature of decimals, and use the nature of decimals to solve related problems.
Teaching difficulty: Understanding the concept of decimal nature is the difficulty in this section. Teaching process:
First, the introduction of new courses.
In shops, the price tag of goods is often written in decimal places like this: gloves are 2.50 yuan, towels are 3.00 yuan. How much are 2.50 yuan and 3.00 yuan here? (2.50 yuan is 2 yuan 50 points, and 3.00 yuan is 3 yuan) Why can you write like this? This is an important property of decimals, and it is also what we are going to learn today. We will write "the property of decimals" on the blackboard.
Second, learn new knowledge.
1, study the properties of decimals.
(1) (blackboard "1") Teacher: At the end of "1", add 1 "and two" 0s "in turn. Has the number changed? How to change it? Can you fill in the appropriate unit name in brackets to make the following equation hold?
1( )= 10( )= 100( )
It is concluded that: 1 yuan = 10 angle = 100 point.
1 m = 10 decimeter = 100 cm
1 decimeter =10cm =100mm
Show me the meter scale. 1 decimeter is110 meter. What decimal numbers can you write? (0. 1m)； 10cm is101100m. What can be written as a decimal number? (0. 10 m), 100 mm is10011000 m What can be written as a decimal? (0. 100 m)
Blackboard: Because 1 decimeter =10cm =100mm.
So 0.1m = 0.10m = 0.100m.
Teacher: Are 0. 1, 0. 10 and 0. 100 equal? Why?
(blackboard writing: 0.1= 0.10 = 0.100)
A, looking from left to right, what is the situation? (Add "0" after the decimal point, and the decimal size remains unchanged)
B, looking from right to left, what is the situation? (Remove the "0" after the decimal point, and the size of the decimal point remains the same)
C, from this, what rules have you found? (Add "0" or delete "0" at the end of the decimal, and the decimal size remains the same)
(2) Display: 0.3 yuan, 0.30 yuan Teacher: Are these two numbers equal? Tell me why. (Students communicate, and teachers guide them appropriately and timely)
(3) Ask students to represent 0.30 and 0.3 respectively on two square papers of the same size (one of which is divided into 100 squares and the other is divided into 10 squares), and compare their sizes, showing that 301100 is three1.
(4) Teacher: What if you add two zeros and three zeros at the end of them? Are they equal? Why?
(5)0.03 plus "0" is 0.3, has the size changed? Why?
(6) Guide students to summarize the nature of decimals.
2. The application of decimal property
Teacher: According to this property, when there is a "0" at the end of the decimal, it is generally possible to remove the "0" at the end and simplify the decimal.
(1) Simplified decimal number Example 6: Question: Which "0" can be removed from the price list?
Q: What is the basis for this? After understanding the meaning of the question, the students answered and the teacher wrote on the blackboard: 2.80 = 2.84.00 = 410.50 =10.5.
(2) Rewrite the integer or decimal to the decimal of the specified number.
Teacher: Sometimes, you can add "0" after the decimal point; You can also put a decimal point in the lower right corner of the integer, and then add "0" to write the integer as a decimal.
For example, 2.5 yuan = 2.50 yuan and 3 yuan = 3.00 yuan.
(3) Give it a try.
0.4=0.400 3. 16=3. 160 10= 10.000
Practice: Answer the second question of "Practice" orally.
Discussion summary: When rewriting decimals, we must pay attention to the following three points:
A, do not change the size of the original number;
B only "0" can be added after the decimal point;
C. When rewriting an integer into a decimal, you must first add "0" after the decimal point in the lower right corner of the integer. (Think about why)
Third, consolidate the practice.
(1) According to the nature of decimal system, when there is a 0 at the end of decimal system, the end can generally be removed.
0. would you like to have a try？
Show the layered test card. Page 34 Basic Exercise 2. Which of the following numbers can be 0 >>
Question 6: The significance of decimal numbers in the fourth grade of primary school. Teacher's teaching plan 1. Writing teaching cases is a way for teachers to constantly reflect and improve their own teaching, which can make teachers more deeply aware of the key and difficult points in their work. This process is the process of teachers' self-education and growth.
2. The process of teachers writing teaching cases is the process of mutual transformation between external education theory and internal teaching theory, which can provide rich practical situations for new teachers and in-service teachers, help to integrate theory with practice in teaching and cultivate the ability to analyze and solve problems.
3. Teaching cases are a true and typical record of teachers' teaching behavior, a true embodiment of teachers' teaching ideas and concepts, a valuable resource for education and teaching research, and an important medium for communication between teachers.
Question 7: How to write the meaning and nature of decimals in the review class;
1. Make students further understand the meaning of decimals, know the counting unit of decimals, and master the nature of decimals and the law of decimal size change caused by decimal position movement.
2. Let the students rewrite decimal and decimal composite; Enable students to reserve a certain number of decimal places as required by the "rounding method", find out the approximate number of decimal places, and rewrite the larger number into decimals in units of ten thousand or one hundred million.
3. Cultivate students' good study habits of arranging knowledge. Teaching emphases and difficulties:
1. Master the nature of decimal and the law of decimal size change caused by decimal position movement. 2. Let the students rewrite decimal and decimal composite; Enable students to reserve a certain number of decimal places as required by the "rounding method", find out the approximate number of decimal places, and rewrite the larger number into decimals in units of ten thousand or one hundred million.
Teaching process: 1. Review 1. The teacher shows the context diagram of knowledge.