Unit goal:

1. Understand the meaning of percentage and its application in practice, and you will read and write percentage correctly.

2. Be able to exchange decimals, fractions and percentages.

3, understand the meaning of discount, tax, interest, know their simple application in life, will do a simple calculation in this respect.

4. On the basis of understanding and analyzing the quantitative relationship, students can correctly answer the questions about percentage.

Unit focus:

The meaning of percentage, find the application problem that one number is a few percent of another.

Unit difficulty:

More complicated percentage application problem.

Significance and writing method of topic percentage

New lesson preparation teachers based on class

Subclass 1 general class general class general class

Teaching target knowledge

Use skills to make students understand the meaning of percentage; Be able to read and write percentages correctly and use percentages to solve simple practical problems.

Problem solving and mathematical thinking enable students to experience the process of collecting, analyzing and processing information, and cultivate students' ability of analysis, comparison, abstraction and generalization, as well as their ability of communication and cooperation with others.

mood

And at the same time, students are educated with relevant information.

The meaning and writing of key percentage.

The connection and difference between difficulty percentage and score

Teaching process teaching is based on individual modification.

Review of goal-oriented learning to stimulate interest, goal-oriented learning, independent cooperation, report exchange and variant training

Create a suspicious environment (1) to introduce dialogue and reveal topics. (2 minutes)

Teacher: Students, before class, the teacher asked everyone to collect the percentage of life. Did you collect it? Where did you collect it? Is it easy to find? What does this mean?

Since percentages are so useful, shall we study percentages in this course? What do you want to know about percentages?

In this lesson, we focus on the meaning and writing of percentage. (blackboard writing topic)

Cooperative inquiry (2) Explore the meaning and writing of percentage. (20 minutes)

1, the meaning of percentage

Teacher: Please look at the big screen: (showing three cups of sugar water)

Which cup of sugar water do you think is sweeter?

The students came to a bad conclusion after arguing.

The teacher gave the sugar content of three cups of sugar water: 7g,13g, 9g. Q: Can you judge now? What else do you need?

Give the weight of sugar water: 20g, 50g, 25g. Q: Can you judge now? See what?

Health: See how much sugar is in the syrup?

Write on the blackboard according to the students' answers:

Teacher: Can you tell which cup is sweeter? How can it be easily seen? (Total score)

Teacher: Percent means the multiple relationship between two quantities, which is a fraction and cannot be followed by the company name, so percentage is also called percentage or percentage. (blackboard writing)

2, the percentage of writing:

Teacher: Percentages are usually expressed by adding a percent sign% after the original molecules instead of fractions. The teacher demonstrated writing 35%.

Ask one student to play 26% and 36%, and the other students write in this book.

Teacher-student communication: how to write a standard percentage of beauty?

(1) Write the two small circles smaller. (2) the inclination of the diagonal.

Judging from the bad judgment just now, it is clear at a glance who helped us. Everyone collected a lot of life percentages before class. Can you tell me the specific meaning of these percentages now? Ok, let's talk in groups of four. Tell me about your percentage. What do you mean?

Who wants to show you the percentage you collected? Talk about its significance.

4. The teacher also collected some percentages. Do you want to see them?

Show courseware: reading.

(1) The cultivated land in China accounts for 7% of the world's cultivated land;

(2) China accounts for 22% of the world population;

(3) At the Beijing Olympic Games, China athletes won 5 1 gold medals, accounting for16.9% of the total gold medals;

(4) China's success rate in launching satellites is 100%.

Do you know what these percentages mean?

What do you want to say after reading this message?

(3) The difference and connection between percentage and score. (5 minutes)

1. Group discussion: What is the difference and connection between percentage and score?

2. Student report:

Students may answer: ① Differences in numerator, denominator, pronunciation and meaning.

Courseware demonstration:

Which of the following scores can be expressed as a percentage? Which can't? Tell me why.

A pile of tons of coal was transported away.

Is percentage a fraction? Is the fraction with denominator 100 a percentage?

It is concluded that a fraction can represent the multiple relationship between two numbers or a specific number, and a percentage can only represent the multiple relationship between two numbers. Percentages are special scores.

Expand the application of 1. Percentages are everywhere in our lives, and there are also percentages in idioms.

Courseware demonstration: Please express the following words in percentage.

Win every battle, kill two birds with one stone

(Design intention: Let students realize that there is mathematics everywhere in their lives)

Total score 1. Are you satisfied with your performance in this class? Use percentage to express your satisfaction.

2. Are you satisfied with your teacher? Also expressed as a percentage.

Finally, the teacher gave the students a famous saying to encourage them.

Genius =99% sweat+1% inspiration.

Do your homework.

Significance and writing method of design percentage of blackboard writing

14% Reading: 14%

65.5% reading: 65.5%

120% reading: 120%

Interchange of topic percentage and decimal

Subclass, class 2, class 1, class 1.

Teaching target knowledge

With skills, students can understand and master the conversion methods of percentages and decimals, and can correctly convert decimals into percentages or decimals; In the process of calculating, comparing, analyzing and exploring the relationship between percentages and decimals, students' abstract generalization ability is cultivated.

Problem solving and mathematical thinking stimulate students' awareness of mathematical exploration by exploring the mutual transformation law of percentage, fraction and decimal.

mood

Under the careful guidance of teachers, students with attitudes actively participate in mathematics activities, draw conclusions through cooperation and exchange, and improve mathematics literacy.

The method of conversion between key percentages and decimals can correctly realize the conversion between them.

The method of conversion between percentages and decimals in difficult induction.

Teaching process teaching is based on individual modification.

Review of goal-oriented learning to stimulate interest, goal-oriented learning, independent cooperation, report exchange and variant training

Create a situation and arouse suspicion. 1. Review and import.

What do you mean by 1 and percentage? The students answered.

Health 1: The number with the percent sign is called the percentage.

Health 2: A number that indicates that one number is a percentage of another number is called a percentage.

2. What's the difference between percentage and score? Why list percentages in separate units?

Percent refers to the multiple relationship between two numbers, also called percentage or percentage, and cannot take the unit of measurement; Fraction can not only represent the multiple relationship between two numbers, but also represent specific quantities and energy band measurement units.

Percent and fraction are both related and different, and are widely used in life, so it is necessary to be a separate unit.

3. We learned integers, decimals, fractions, percentages and blackboard writing.

Cooperative inquiry II. What do you want to know when you see this topic?

Health 1: why the transformation?

Student 2: How to transform?

Teacher: Yes, why do you want to transform each other? Guide students to say the meaning of transformation. One is easy to calculate and the other is easy to compare. (blackboard writing), how to translate it? This is our main research content today. However, how to convert percentages into decimals and how to convert decimals into percentages? The teacher wants to give you the podium, let the students be little teachers, and let the podium become your stage.

Third, cooperative inquiry, learning new knowledge

1, 84 pages (two minutes) of self-study materials for students.

2. Panel discussion (three minutes)

3, refers to the students report on stage, the collective exchange of decimal into percentile method.

(1) Give an example of 1

(2) Teacher A: To convert decimals into percentages, we must first convert decimals into fractions capitalized as 100, and then rewrite this fraction into percentages.

3? 5=0.6= =60%

4? 6? 0.667 = =66.7%

(3) Teacher B: Please observe this process. It is a bit troublesome to change decimals into fractions first. And I can directly convert decimals into percentages. Just move the decimal point two places to the right and add hundreds of semicolons at the end.

(4) Teacher's explanation: If the decimal point is moved two places to the right, the original number will be expanded by 100 times, and it will be reduced by 100 times by adding hundreds of semicolons. So the size of the original number is constant.

4. Teacher: I'm tired of studying here. Have you learned everything you want to learn today? No, I haven't learned how to convert percentages into decimals. ) Well, let's learn how to convert percentages into decimals.

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