The fourth grade "The Meaning of Fractions" says that the draft is 1. First of all, the textbook says:
The significance of fractions is taught on the basis that the fourth-grade students have preliminarily understood fractions and know that an object and a unit of measurement can be divided into several parts on average, and one or several parts can be expressed by fractions. The key point is to make students understand that not only an object, but also a unit of measurement can be represented by a natural number 1, and a whole composed of many objects can also be represented by a natural number 1, usually called the unit "1", and then summarize the meaning of the score. Learning this part well will lay a solid foundation for the construction of the following concepts such as true score and false score, as well as for learning the basic properties of score, four operations of score and application problems of score.
(A) Teaching objectives
Combining the students' existing knowledge and experience and my understanding of the teaching materials, I have established the teaching objectives, teaching emphases and difficulties of this course:
Knowledge goal:
1 With the help of intuitive operation and display, experience the construction process of "fractional meaning" in activities such as speaking, division, drawing, writing, folding and drawing, understand the unit "1", and communicate the connection and difference between fractions and integers.
2. Understand the meanings expressed by the names, numerator and denominator of each part of the score, understand the meaning of the unit of the score, experience rich realistic situations, and perceive the rich connotation of the score through specific quantities.
Ability goal:
Through intuitive teaching and hands-on operation, students can understand and form the concept of score on the basis of full perception; Cultivate students' practical ability, observation ability and innovation ability, and promote the development of thinking; Through the cooperation among students, it can promote the cultivation of students' good study habits such as listening to lectures and asking questions.
Emotional goals:
Understand the close relationship between scores and life, and experience the fun and success of learning mathematics.
(B) the focus of teaching
The induction of fractional meaning and the unit "1". Abstraction.
(C) Teaching difficulties
"1" is a whole composed of multiple objects.
Second, teaching methods:
Students know things from easy to difficult, and step by step from shallow to deep. Although students have a preliminary understanding of the score in their previous study, they must follow their cognitive rules in order to understand the concept of unit "1" and further clarify the meaning of the score. Therefore, this course adheres to the principle of taking students as the main body and teachers as the leading factor. Teaching methods such as creating scenes, inspiring and inducing, self-exploration and hands-on operation are adopted, and intuitive demonstrations are interspersed. Through hands-on operation and intuitive demonstration, let students fully perceive, and then through comparison and induction, break through the difficulty that a whole composed of many objects can also be regarded as the unit "1", step by step, and understand the meaning of scores on this basis, so as to cultivate students' various abilities.
Third, the methods of speaking and learning:
Students' learning process is always inseparable from the method of starting school. In the teaching of this course, the guidance of learning method runs through the whole teaching process.
1. Teach students how to explore knowledge. Teachers provide students with some practical materials,
Round cake model, square paper, four apples, a one-meter-long rope. Let the students use these learning tools to divide them into a point in the form of group cooperation, draw a picture, fold it up and cut it into a quarter. Then observe and compare their similarities and differences, and realize that the unit "1" can be not only an object, a unit of measurement, but also a whole composed of many objects, thus realizing the sublimation from perceptual knowledge to rational knowledge.
2. Guide students to master the method of summarizing the essence of things while acquiring knowledge. After hands-on operation and comparison, the students come to the conclusion that the unit "1" can also be a whole composed of many objects. Ask the students to operate it twice, and realize that the score is different because of the number of copies of the score. On this basis, further clarify the meaning of the score and summarize it: divide the unit "1" into several shares on average to represent such a number or share, which is called a score.
Fourth, talk about teaching procedures:
According to students' cognitive law of "perception-representation-abstraction", the teaching methods of creating situations, hands-on operation and independent inquiry are mainly adopted in teaching, that is, giving students the right and time to ask, speak, say and do, striving to create a relaxed and democratic learning atmosphere for students, fully mobilizing students' senses such as eyes, mouth, brain and hands to participate in cognitive activities, so that children can truly feel "I can do it".
(a) Creating scenarios and introducing new knowledge:
The Tang Priest and his disciples went to the West to learn Buddhist scriptures. One day, on the road, they all felt hungry and thirsty. Master told Wukong to find something to eat. After a while, Wukong brought back a big watermelon. The master asked Wukong to divide the watermelon into four parts equally, and everyone shared one. Just after eating, Bajie couldn't wait to grab a piece. Then the master asked, "Bajie, can you tell me how many watermelons you have in your hand?" Can you express it in a number? "Eight quit scratching their heads, how also can't figure out how to express.
Clever classmate, can you help Bajie say what number is used to represent the watermelon in his hand? How many should there be?
Through the introduction of creating scenes, not only the score is reproduced, but also the students understand the inevitability and necessity of the score. Let the students feel satisfied in the story and be interested in the academic scores, so as to ask questions naturally.
Revealing the theme: the generation and significance of scores
(B) to understand the history of music:
Scores are derived from integrals. In primitive society, people worked collectively and distributed fruits and prey equally, and the concept of score gradually emerged. In the future, in the process of land calculation, civil engineering, water conservancy engineering and other measurement, when the integer result is not obtained, a score will be generated.
The design of this link shows the development history of scores, stimulates students' interest in learning and actively spreads mathematics culture.
(3) Hands-on operation
Operation score
Perceived unit "1"
(1) Draw, draw, draw a quarter of the round cake model.
(2) Fold the square paper into four equal parts and paint one of them with your favorite color.
(3) One point, four apples for four students.
(4) cut once. 1 meter-long rope is cut into four parts on average, indicating one part.
After the students begin to operate, throw questions and let the students show a heated discussion:
What did you find in representing a quarter?
The design intention of this link is based on students' existing knowledge and experience (an object and a unit of measurement can be regarded as a whole). Through the transmission of knowledge and experience, it is learned that many objects can also be regarded as a whole, and this whole can be expressed by natural number 1, usually called unit "1", thus highlighting the rich meaning of unit "1".
Understand meaning and fractional units.
The design of this link is based on students' full perception of the meaning of the unit "1", so that students can operate again and intuitively perceive the meaning of the score and the unit of the score. At the same time, through specific operations, I learned that because the number of points is different, the decimal unit is also different, what is the denominator, and the decimal unit is the fraction. At the same time, actively encourage students to express their understanding of concepts in their own language.
(4) apply what you have learned:
In this link, the teacher adjusts the teaching in time according to the feedback information from the students, so that the students can effectively master the knowledge and achieve the purpose of training and improvement. In order to combine teaching students in accordance with their aptitude and make every student successful, I designed the following exercises:
1. Basic knowledge exercise: The purpose is to highlight the key and difficult points of this lesson and deepen the understanding of the meaning of fractions.
2. Talking about' scores' in life: This topic aims to cultivate the broadness and flexibility of students' thinking.
(5) class summary
"In this class, we learned the meaning of music together, got a better understanding of music, and had a lot of knowledge about music! Students continue to learn and explore after class! " The teacher extended the students' interest in learning to the next class.
Five, the blackboard design:
The design of blackboard writing is a whole, which highlights the difficulty of this lesson: "unit 1" is actually to explain to students that many things in real life can be regarded as a whole, that is, Unit 1.
Lecture 2 1 on the meaning of fractions in grade four, the structure and position of this unit.
The significance of the score lies in the first lesson of Unit 4 in the second volume of Grade Four. This unit is the beginning of students' systematic learning scores. The main study contents include: the meaning of fraction, the relationship between fraction and division, true fraction and false fraction, the basic properties of fraction, the greatest common factor and divisor, the least common multiple and general fraction, and the relationship between fraction and decimal.
In the last semester of grade three, students got a preliminary understanding of the score with the help of operation, intuition and the names and meanings of each part of the score. They can read and write simple fractions, compare fractions with the same denominator and learn simple addition and subtraction of fractions with the same denominator. All these have laid the foundation for the research of this unit.
2. Teaching objectives
Make students understand how the score is produced, understand the meaning of the score and the unit of 1, know the meaning of the numerator, denominator and unit of the score, and cultivate students' abstract generalization ability in the process of inquiry learning.
3. Teaching focus
Understand the generation and significance of the score and know the unit of the score.
4. Teaching difficulties
Understanding unit 1.
Teaching methods:
Traction method:
Students have been able to divide an object into several parts on average, and can accurately express the size of each part with scores. Therefore, I guide students to make the transition from dividing an object equally to dividing some objects equally, and knowledge guides the transition, which reduces the learning difficulty.
Induction:
By the third grade, students have a preliminary understanding of the score. This lesson guides students to divide some objects into equal parts and get some scores. On the original basis, they have a deeper understanding of the score, and then sum up the meaning of the score.
Guiding practice method:
After students understand the meaning and unit of the score, they can deepen their understanding of the concept through several groups of exercises.
Speaking and learning methods:
Discuss the meaning of scores in groups.
Let the students know what the unit 1 is and how many copies are there on average. What do these copies mean? After students think independently, discuss, communicate and report in groups to understand the specific meaning of each score.
Talking about the teaching process:
First, the introduction of new courses.
Ask the students to guess riddles before class, stimulate their curiosity and thirst for knowledge, and lead to the teaching content of this lesson. Such as: split into two, wholeheartedly, seven ups and downs.
Second, explore new knowledge.
1, understanding the generation and significance of scores (courseware demonstration)
(1) Divide 1 apple into two parts. How much is each part? How to express this one? Can it be expressed as an integer?
(2) The courseware shows pictures of apples. Students use scores to express and ask what they have found. Students discuss and communicate.
(3) Teacher-guided induction: the generation and significance of scores.
2. Understanding unit 1
I have prepared a number of different objects for each group, so that students can divide them by the method of average score. In the process of division, students can find out different points.
(1) The teacher emphasized the meaning of the unit 1, which not only refers to an object, but also refers to some objects. (Courseware demonstration)
(2) Students' examples: deepen the understanding of 1 unit.
(3) Description: the unit 1 can represent an object or some objects, and the unit 1 can be large or small.
3, let students learn the score unit by themselves (show courseware teaching)
(1) introduces the concept of fractional units and emphasizes one of them.
(2) Complete the guide of P64 Question 8. Tell the students what to do, read the scores and say the unit of each score.
Third, the application of new knowledge.
Show the exercises in the courseware for students to do, answer by name in class and correct them collectively. Group competition, high learning enthusiasm.
Fourth, class summary.
Students discuss in groups, representatives speak, and teachers summarize.
Say blackboard writing design:
Write the three knowledge points of this lesson on the blackboard, focusing on the meaning of score and the concepts of several score units, so as to be clear and focused.