1, understand the generation of fractions, understand the meaning of fractions, and clarify the relationship between fractions and division.

2. Knowing the true score and the false score, knowing that the fractional score is another way to write the false score, you can turn the false score into a fractional score or an integer.

3. Understand and master the basic properties of fractions, and use the basic properties of fractions to turn fractions with different denominators into fractions with the same size.

4. Understand the meaning of common factor and greatest common factor, common multiple and minimum common multiple, find out the greatest common factor and minimum common multiple of two numbers, skillfully carry out division and division operation, and compare scores.

Teaching emphases and difficulties:

1, master the basic properties of fractions, and use the basic properties of fractions to turn fractions with different denominators into fractions with the same size.

2. Understand the meaning of common factor and greatest common factor, common multiple and minimum common multiple, find out the greatest common factor and minimum common multiple of two numbers, skillfully carry out division and division operation, and compare scores.

Teaching methods and learning methods:

1. In teaching, make full use of teaching resources and guide students to observe, discover and summarize, so as to play the supporting role of life experience in image thinking and abstract thinking.

2. In teaching, while strengthening intuitive teaching, we should also pay attention to guiding students to discuss and communicate in groups on the basis of obtaining enough perceptual knowledge, summarizing with examples and charts, and constructing the connotation of knowledge.

3. In teaching, we should pay attention to students' experience of learning process, so that students can firmly grasp knowledge in the process of comparison, migration and reasoning.

Class arrangement: 15 class hours

The significance and nature of the first grade score

Teaching content: the meaning and nature of scores (page 52 of the textbook)

Teaching objective: 1. Understand the generation and significance of scores. 2. Understand the meaning of unit "1" and decimal unit. Teaching emphasis: understanding and mastering the meaning of scores.

Teaching difficulty: understanding the meaning of unit "1" and decimal unit. Teaching preparation: multimedia courseware, square paper

Teaching process:

First, review the import?

1, ask questions:

(1) Give six apples to two children equally. How much per person? (3)

(2) Divide 1 apple to two children on average. How many apples are there for each child? Everyone gets this apple.

12, taking 2 as an example, tell me the names of each part of the score.

1) 23. Secret topic: In real life, when people measure, divide things or calculate, they often can't get integer results. At this time, it is often expressed by scores. In this lesson, we will learn "the generation and significance of fractions" (blackboard writing topic)

Second, explore new knowledge.

1, guide students to preview new knowledge.

Ask the students to teach themselves the relevant contents on pages 45-46 of the textbook, and then complete the exercises related to "autonomous learning" and record the questions. The exercise is as follows:

What do you mean by123 (1) 7,9,5?

(2) Fill in the blanks

Xiao Chen's mother bought five apples, and the total number of each apple is ().

(2) Xiaoqing's mother bought a box of biscuits, which contained 12 pieces, and each piece belonged to this box of biscuits ().

The decimal unit of 7③ 12 is (), and it has () such decimal units.

2. Self-test.

Organize students to check each other and exchange questions.

3. Guide students to ask questions.

Teachers patrol, participate in students' discussions, give appropriate guidance, collect students' concentrated questions and then answer them.

Third, organize students to explore cooperatively and show their achievements.

1, the teacher shows the exercises corresponding to the knowledge points, emphasizing independent completion. The exercise is as follows:

(1) Fill in the blanks.

① Divide 15 strawberries into 4 parts on average, each part belongs to these strawberries () and 3 parts belong to these strawberries ().

() 7 in 2 14 127 and () 15.

(2) Xiao Jia plans to finish reading Mickey Mouse's math in seven days. How many parts of this book does she read on average every day? How many parts of this book can I finish reading in five days?

2. Communicate your own conclusions in the group.

3. The teacher randomly checks 2-3 groups of speeches for evaluation.

4. Teacher's summary: Divide the unit "1" into several parts on average. The number representing such a part or a few points is called a score, and the number representing a part is called a fractional unit.

Fourth, the basic training in class.

Complete 1, 2, 3 and 4 of Exercise 8 on page 56 of the textbook independently. Fifth, class summary.

What did you get from this lesson? Blackboard design:

Generation and significance of scores

An object

A unit of measurement, a whole → unit "1", some objects.

Divide the unit "1" into several parts equally. The number representing such a part or points is called a fraction, and the number representing a part is called a fractional unit.

The second teaching goal of fifth grade mathematics is "the meaning and nature of fractions";

Knowledge and skills: Through effective mathematical activities, students can understand the meaning of true score and false score, and can correctly distinguish true score from false score.

Process and Method: Through effective mathematical activities, students can experience the process of inquiry, learn through independent inquiry and cooperative communication, and cultivate the ability of observation, comparison, abstraction and generalization.

Emotion, attitude and values: Let students experience the joy of inquiry learning.

Teaching emphases and difficulties:

Only by understanding the meaning and characteristics of true and false points can we correctly distinguish true and false points.

Preparation of teaching and learning tools: courseware, watercolor pen, paper, etc.

Teaching process:

First, create situations and introduce new lessons.

Students, we have been making friends with scores. So what can be expressed by scores? Can you talk about it? A piece of paper, a line segment, a circle and a pile of apples can all be divided equally, resulting in scores. ) Let's call it the unit "1". (blackboard writing: unit "1")

Second, explore new knowledge.

(1) Hands-on operation to collect scores. (Operating materials provided: three sheets of paper. )

1, fold a fraction at will.

Teacher: Next, please take out a piece of paper. Can this paper be counted as "1"? Then ask the students to take out the watercolor pen, fold this paper and draw a music score you like.

Students grade and report (and put it on the blackboard).

2, let the students say that the score is discounted.

The students have just expressed their favorite scores. Who will give us a discount on scores?

(1) Students tell the true score.

Such as: 3/4 discount. Show it to the students after the discount.

Teacher: How do you express this score? Divide a piece of paper into x parts and draw such x parts. )

Teacher: Who calculates the unit "1"? What is a fractional unit? How many such decimal units are there? It is smaller than a piece of paper. That is, less than the unit "1". How many such fractional units can fill this paper?

(Then ask the students to give a discount on scores. If the score is true, let the students think about it and then say it. )

(2) Students lied about their scores.

For example, fold "4/4". Show it to the students after the discount. Teacher: What is the significance of this score? What is its decimal unit? How many such decimal units are there? How much is 1/4? It happens to be a piece of paper. That is, it is equal to the unit "1".

Such as "5/4".

Teacher: Who can tell me what 5/4 means? Can you show it?

Discuss the problem in groups. (Student activities)

Name the students and show them 5/4 on the stage. (Student Report)

Ask the students freely about the pictures shown, and the students will answer.

What if a piece of paper is not enough? Why should the second piece of paper be divided into x equally? What is the unit of this score "1"? Is it ok to regard two pieces of paper as the unit "1"? )

The conclusion is larger than a piece of paper, that is, larger than the unit "1".

Ask the students to say a few more such scores (on the blackboard) and let them think about how to fold them.

(2) Classify the scores and summarize the concepts.

Teacher: There are so many marks on the blackboard now. If Mr. Chen asks you to classify these scores, can you divide them? What criteria are you going to use to divide it?

1. Students discuss and work in groups and classify the scores.

2. Students report and teachers write on the blackboard.

3. Summarize the characteristics of true marks and false marks and write them on the blackboard.

4. Students read the concept of true and false scores.

Third, practical application.

1. Judge whether the following scores are true or false. (Courseware demonstration)

2. Tell the true and false scores with denominator 17 and numerator 17.

3. Use the fraction to represent the color part of each graph. (Courseware demonstration)

4. Judges

Fourth, the class summary:

What do you know about grades through the research in this class?

Five, the blackboard design:

True score and false score

molecule

False fraction of numerator ≥ denominator ≥ 1

The third teaching process of "the meaning and nature of fractions" in fifth grade mathematics

First, review old knowledge and introduce new lessons.

Dialogue: We have learned the preliminary understanding of fractions. What do you already know about grades? Say the parts of the score with examples, and say the meaning of the score with practice.

Talk about: What other music scores do you want to know, and then introduce the new lesson.

Second, cooperative exploration, building new knowledge

(1) Preliminary perception.

Show the scene map 1 "Ship Model Trial".

The teacher said: Students, please look at this picture carefully. What math can you find from it?

Information? What math question are you asking?

The teacher leads the students to ask questions: Five airplane models are distributed to five students equally. How many airplane models does each student get?

Divide the students into groups and score one point with the title cards with five ship models. Students think independently first, then exchange ideas in the group, and finally communicate in the class. Find a solution to the problem. When students work in groups, teachers participate in students' group study. Then communicate in class. When communicating with the whole class, the teacher should guide in time: regard the five ship models as a whole and divide them into five parts on average, 1kloc-0//5.

On the basis of learning 1/5, teachers can continue to guide students to ask questions: for example, what percentage of the total number of airplane models is shared by two students and three students?

(2) Further exploration

Show scene picture 2 "flying model plane"

Students, the model plane is about to fly. Let's go and have a look. Please look at this picture. According to the information in the picture, what questions can you ask about the score?

Students ask questions and the teacher arranges them in time.

For example, what percentage of the total number of aircraft released by a small team in each group? Where's Team Two?

Students use the learning tools in their hands to put a pendulum, divide it into one point, and solve the problem of "how many planes do a small team fly in each group?" What about the second team? "

Solve the first problem: students study in groups, and teachers should participate in students' group activities.

When communicating with the whole class, students pose with four airplane models first, and may have 1/2 and 2/4 answers. Then the whole class communicates, analyzes, supplements and draws a conclusion. Teacher's timely guidance: each is two planes, why is it a whole 1/2?

The conclusion of the first question is drawn through the pendulum model: the four planes are regarded as a whole and divided into two parts on average, and each part accounts for 1/2 of the whole.

The courseware demonstrates the process of bisecting four planes and draws a conclusion on the blackboard.

Solve the second question: let the students exchange answers first; Then organize students to do hands-on verification and participate in students' learning activities; When communicating with the whole class, you should be prompted: "There are two planes each, why do they account for 1/3 of the total?" . So as to guide students to draw conclusions.

(3) Observation and comparison

Talk: Please observe our scores. Do you have any questions?

Guide the students to ask questions: each team releases two planes. Why do they show different scores?

Students observe and compare, discuss at the same table, and communicate with the whole class to draw a conclusion.

By comparing the flight situation of two small teams, it is concluded that the average number of shares divided into a whole is different, and the scores are also different. So the two planes are the same, and the marked scores are 1/2 and 1/3.

(D) Expand the application

Dialogue: Think about it, what else can be regarded as a whole? You can use the information provided by the teacher, or you can find your own information and do it yourself. What score can I get? How did you get it?

Students can use the materials provided by the teacher (1 rectangular piece of paper, 8 sticks and 1 meter rope) or find their own materials to get different scores.

Communication: What materials were used, how many points were scored and how did you get them?

Summary: divide a whole into several parts on average, and such one or several parts can be expressed by scores.

(5) Summary

Dialogue: An object, a unit of measurement and a whole composed of many objects can all be represented by a natural number 1, usually called the unit "1".

For example, what other quantities can students take as the unit "1"? And distinguish between the unit "1" and the natural number 1.

Discuss, communicate and summarize the significance of the score in combination with the operation process. Guide students to sum up the significance of summing up scores. Divide the unit "1" into several parts on average, and the number representing such a part or parts is called a fraction.

(6) reading questions.

Students read pages 67-69, ask questions and ask difficult questions. Teachers patrol to answer students' confused and difficult questions.

Third, skillfully set exercises to deepen understanding

1, independent exercise 1, 2

2. Can the colored parts be expressed by fractions? (Courseware demonstration)

3. Game: "Take candy." Students take candy as required: there are 1 1 pieces of candy in the box, and take out 2/11of the total; Take out the remaining1/9; Then take out the remaining 1/4; If you take out two dollars, how much will you take out the rest? ……

Do it independently and communicate.