Three Mathematics Coursewares "Percent Understanding"

1. Knowledge goal: Understand the meaning of percentage in specific situations and read and write percentage correctly.

2. Ability goal: to cultivate students' learning ability of observing, thinking, comparing, analyzing, summarizing, communicating with others and cooperative learning in the process of cooperative learning.

3. Emotional goal: let students feel the close connection between mathematics and life, and enhance the enthusiasm of mathematics learning. Cultivate students' good thinking habits.

Second, the teaching focus:

The meaning, reading and writing of percentage.

Third, the teaching difficulties:

The connection and difference between percentage and score.

Four, the preparation of teaching AIDS and learning tools:

Percentage courseware, percentage collected by students, and several small CDs.

Fourth, the teaching process

(A) show the percentage, lead to explore questions.

1. Talk: Students, after class, I will arrange for everyone to find the percentage and show the percentage you found to your classmates. Is the percentage easy to find? Suddenly, the teacher thought of a problem: people like percentages so much. What are the benefits of percentage? What else do you want to know about percentages? Tell me.

We can solve these problems by reading books and discussing with each other. Let us study them in your own way, shall we?

3. Tell me about your research and share it with everyone.

(2) Teachers and students discuss the meaning, reading and writing of percentage.

A: Show the questions and communicate in groups:

Teacher: Your research is really good. Do you want to have a deeper understanding of these problems? Ok, class, mathematics is the most reasonable science. Let's look at the following question: In a football match, the Tigers got a chance to take the penalty kick, and they are going to send one of the following three players to take the penalty kick.

Player No.7: I once punished 20 penalty kicks, which hit 18.

No.3 player: once took a penalty of 10, and scored 7 penalties.

Player No.5: I once took 25 penalties and scored 2 1.

Who do you think should be sent to take the penalty (show the empty form)? Please share your thoughts in the group.

B: Communicate and report the group's ideas in class.

1. Students exchange ideas in their own groups.

2. Teacher's summary: Because the total number of penalty kicks is different from the number of balls punished by three people, in order to know who to send accurately, it is very simple to first calculate the number of balls punished by players in the total number of penalty kicks, and then divide these scores by the score that the mother is 100, and then compare them.

C: Teaching percentage of writing and reading.

1. Teacher: Like this, the denominator is a fraction of 100, and we usually write it as a percentage. We usually write it like this-remove the fractional line, write the numerator 90 first, and then write the percentage sign (on the blackboard: 90%). How to write the percentage sign in teaching (the teacher pays attention to the writing order of "%"when writing the percentage sign on the blackboard)

Teacher: What should I pay attention to when writing a percentage sign?

Teacher: Yes, you should write a circle first, then a diagonal line, and then a circle. Be careful not to write too big a circle. So as not to be confused with the number "0". The whole class is free to write it again. Ask the students to write down the other two percentages and evaluate them.

The significance of teaching percentage

1, the percentage that the teacher said: Can you understand it? Let's read it together!

90% (read on the blackboard: 90%) and then read 70% and 84%.

Teacher: Students, we can already write and read percentages.

Then the teacher wants to ask you, what do you mean by 90% here (students say 90% means that the number of free throws by player No.5 accounts for 90% of the total number of free throws) and 70% and 84% (the teacher asks more students to say).

2, teachers and students * * * The same inductive blackboard: the number indicating that one number is the percentage of another number is called percentage. ) watch it twice.

Teacher: You see, there are several figures (two figures) mentioned in the meaning of percentage. That percentage means a relationship between them, that is, a percentage means a relationship between two numbers.

Reveal the connection and difference between percentage and score.

1, Teacher: The teacher found some percentages in life before class. Do you want to see them?

The courseware shows the situation map and asks in turn: Who can tell what the percentage here means?

(1) information of the fifth population census;

(2) clothes map and pure juice map;

(3) Statistics of various protein ingredients in food.

(3) Yao Ming map (After answering the teacher: Yao Ming is really the pride of China. I hope he will continue to achieve good results for the motherland. ) The teacher guides the students to find out that there is no such percentage (decimal) in front of them. Teacher: Yes, the numerator of the percentage can be a decimal or an integer.

(4) Statistical chart of the schedule of fifth-grade students (students choose one or two items to explain who accounts for who's percentage)

2. Teacher: Show the courseware: The following four sentences have four scores, which can be written as percentages. Why?

(1) The number of chickens is 60/100 of that of ducks;

(2) The length of rope is 63/100 of the length of iron wire;

(3)- Coal piling, which has transported 60/100t. ;

(4) The weight of flour is 3/4 of that of rice.

After the discussion between teachers and students, the teacher further asked: Why can't 20/100t be written as a percentage? Teacher's summary: percentage is a special kind of score, which only indicates the relationship between two quantities, just as one number is several times that of another, and there is no unit name. It only represents the relationship between two quantities. So percentage is also called percentage or percentage.

(3) Expand application and practice innovation.

Teacher: We have a 40-minute class. How many minutes have passed in this class at X: X:, which is about a few percent of this class. (Students think and answer) Time is running out. Let's go to the math playground together!

1, (courseware demonstration) I can read: 3.9%1%120% 6% 98%100% 300%.

Teacher: Let's read these percentages first.

(1) division; In this group, which percentage is the smallest and which is the closest?

(2) Teacher: Is 1% the minimum percentage? Is there a percentage less than 1% in life? (For example. )

Teacher: By the way, the numerator of percentage can be a decimal or an integer, some of which are larger than the denominator and some are smaller than the denominator.

2. Create percentage:

(Let the students put a small disk first and say the percentage; Then ask the students to look at the grid and say the percentage. Find out for yourself if there is any percentage around you.

(d) New lesson summary, after-school promotion:

1. Teacher: Students, what have you gained from today's study? I didn't expect us to gain a lot in this class. It seems that learning math well can make our life more colorful! .

2. Teacher: The teacher is really happy for you. Look at the following sentence. What courseware do you have in mind? Genius =99% sweat+1% inspiration. (teacher dubbing: genius =99% sweat+1% inspiration. I believe that in learning, as long as you are willing to pay, success will always belong to you! Come on! )。

That's all for today's class. Class is over.

Blackboard design:

Percentage (also called percentage or percentage)

A number indicating that one number is a percentage of another number is called a percentage.

No.7: The number of missed shots is 18/20=90/ 10090% of the total number of free throws.

Third place: ... is 7/ 10=70/ 10070%. ...

5th: ... is 2 1/25=84/ 10084%. ...

Chapter II Teaching Objectives:

1, knowledge goal: understand the necessity of introducing percentage, understand the meaning of percentage, and read percentage correctly. In specific situations, explain the meaning of percentage and realize the close relationship between percentage and daily life.

2. Ability goal: experience the process of abstracting percentage from practical problems and cultivate students' ability of inquiry and induction.

3. Emotional goal: Let students experience the happiness of success in the process of operation and exploration.

Teaching focus:

Through the process of abstracting percentage from practical problems, I realized the necessity of introducing percentage and understood the meaning of percentage.

Teaching difficulties:

The connection and difference between percentage and score.

Teaching preparation:

Students are required to collect percentage data before class.

Teaching process:

First, dialogue import

Teacher: Before class, the teacher asked everyone to collect the percentage of life. Students, have you collected the percentage of life?

Health: I collected it.

Teacher: Say it and communicate with you.

Health: ...

Teacher: Can you tell us where your percentage was collected?

Health 1: on the food label.

Health 2: On the label of socks.

Health 3: ...

Teacher: The teacher also brought some "percentages" today.

Show the theme map on page 77 of the text.

Numbers like the above, such as 18%, 50%, 64.2% ... are called percentages.

Today we are going to learn "percentage". (blackboard writing: percentage)

Teacher: One of the most important aspects in learning is to learn to ask questions. Students, what do you want to know when you see the topic "percentage"?

1: What are the advantages of percentage?

Health 2: What do you mean by percentage?

S3: Is percentage a fraction? What's the difference between this and scores? what is the purpose?

Health 4: ...

Teacher: I'll sort out the students' questions, mainly: benefits, significance and differences (the teacher writes on the blackboard while talking)

Second, independent exploration and abstract generalization.

1, group discussion, experience the benefits of percentage.

Let's play a guessing game.

There are three cups of sugar water. Please guess which is the sweetest?

Cup 1: sugar 18g sugar water 20g second cup: sugar 43g sugar water 50g third cup: sugar 2 1g sugar water 20g.

Let the students guess first, and then compare the total score, and draw the conclusion that 1 cup of sugar water is the sweetest.

==90%==86%==84%

Fractions with a denominator of 100 can be written as "percentage".

Summary: "percentage" is easy to compare and widely used.

2. The meaning of abstract percentage.

These percentages are not length, price or weight, but the relationship between two quantities, and the relationship between them is expressed in the form of a few percent. Therefore, a number that indicates that one number is a percentage of another number is called a percentage, and a percentage is also called a percentage, or a percentage.

3. Reading and writing

4. Discussion: What's the difference between a score and a percentage?

① Different writing forms;

② The fractional units are also different;

③ Different meanings: the score indicates the ratio between two quantities, and can also indicate a specific quantity. Percentages only represent the ratio between two quantities. There is no company name after it.

Percentage is a special kind of score.

Third, consolidate training and expand and extend.

1, say it

(1) The population of China accounts for 22% of the world's total population.

(2) The cultivated land area in China accounts for 7% of the total cultivated land area in the world.

What information can you get from this sentence? What percentage does it mean who is who?

What else can you think of?

On the whole, China has only used 7% of the world's arable land to solve the problem of food and clothing for 22% of the world's population, which is a major event. If the population of China is controlled, for example, the population of China accounts for only 15% of the world, or even less, what will the people's living standards be like? What will be the speed of China's economic construction? (faster)

2. True or false.

(1) The percentage of 50% should be reduced to 1/2.

(2) The wire is 57% meters long.

3, the game, write percentage.

Teacher: Shall we play games?

Please write your favorite percentage of 10 on white paper to see who writes the most creatively! Ready, go! Twenty seconds later. Teacher: Stop! Tell everyone what percentage you wrote.

Health 1: I wrote five, namely: 100%, 1%, 200%, 24.8% and 0.5%.

Health 2: The percentage I wrote is 100%, the smallest …

4. Guess. (in percentage)

A hundred hair and a hundred hits ()

One in a hundred ()

kill two birds with one stone

Half a country ()

A narrow escape ()

(Design intention: Through various exercises, let students further deepen their understanding of percentage, feel the application of percentage in life, discover the connection between mathematics and other disciplines, and establish students' confidence in learning mathematics. )

Fourth, class summary.

Teacher: Please tell us the proportion of your emotions in this class.

Happiness accounts for ()% nervousness accounts for ()% regret accounts for ()%.

Send you a word: success = 99% sweat+1% inspiration, as long as you work hard, you can succeed.

Reflections on "Percent Cognition" Teaching

The main content of this lesson is the meaning of percentage, which is based on students' study of integers, decimals and fractions, especially for solving the problem that "a fraction of one number is a fraction of another". This content is the basis of learning the interaction between percentage and score and solving problems with percentage knowledge, and it is one of the important basic knowledge in primary school mathematics. Percentage is widely used in students' life and social production. Most students are directly or indirectly exposed to some simple percentages and have some scattered perceptual knowledge about percentages. Therefore, in teaching, starting from the actual life of students, I adopt the strategy of students' independent inquiry, cooperation and exchange, supplemented by teachers' guidance, so that students can perceive in life examples, find out in positive speculation and understand the meaning of percentage in specific applications. Mainly reflected in the following two aspects:

First, start with what students are interested in and stimulate their interest in learning.

I organized students to discuss the sugar content of three cups of sugar water, and in the process of comparing which cup of sugar water is the sweetest, the percentage was derived. At this time, the students have vaguely realized that percentage is a number indicating that one number is a fraction of another. For comparison, it is divided into fractions with denominator of 100. Students have initially realized the meaning of percentage and the benefits of using percentage when comparing data.

Second, keep close contact with life and understand the meaning of percentage.

Percentage is the knowledge that is often used in daily production and life. Although the students don't officially know the percentage, they are not ignorant. So I ask students to investigate the percentage in life before class, so that students can realize the wide application of percentage in life and the significance of knowledge to individuals, which plays a very good role in stimulating internal learning motivation. In this class, I directly take the data and questions investigated by students as the objects of study and research. Students know the percentage in the process of understanding and interpreting the data surveyed by themselves and their classmates.

Third, give students the initiative to learn.

In the teaching process of percentage cognition, I involve students from the formulation of learning objectives to the evaluation. "Students, what do you want to know about percentages?" This question has aroused students' desire to study actively. "I wonder what the percentage is?" "I wonder when to use percentages?" "I wonder what's the difference between percentage and score?" ..... After sorting out this series of questions, isn't that the learning goal of this class? After class, I guide students to evaluate themselves in time. "Students, can you evaluate your performance in this class with a hundred-point sentence?" With such a challenging summary, students are scrambling to evaluate themselves. Some people say that I have learned ()% of the knowledge in this class, what knowledge I have learned, what knowledge I have not learned ()% of this class, and what knowledge I have not learned or am still confused; Some students said that I was ()% satisfied with the academic performance of this class, where I was satisfied, ()% dissatisfied, where I didn't perform well; Other students said that I was happy ()%, nervous ()% and sorry ()% in this class. In the whole class, I try to make students develop actively in some autonomous activities.

In the teaching of this course, starting from the students' actual life, I adopt the strategy of students' independent inquiry, cooperation and communication, supplemented by teachers' guidance, so that students can experience the learning process of "perception in examples, discovery in speculation, understanding in application and application in summary". In this pleasant classroom, students' abilities have been developed, their personalities have been publicized, and I have been greatly encouraged and inspired.

Chapter III Teaching Contents:

The Understanding of Percentages, the second volume of the fifth grade primary school mathematics published by Beijing Normal University.

Teaching material analysis:

The understanding of percentage is taught on the basis that students have learned integers, decimals and fractions, especially on the basis of solving the problem of "how much one number is another number". This content is the basis of learning percentages and fractions, reciprocal of decimals and solving problems with percentage knowledge, and it is one of the important basic knowledge in primary school mathematics. Percentage is widely used in students' life and social production. Most students are directly or indirectly exposed to some simple percentages and have some scattered perceptual knowledge about percentages. Therefore, in teaching, I proceed from students' reality, let students perceive and correctly use it to solve practical problems in life examples, and truly realize that "mathematics comes from life and is applied to life". There are two theme situations in the textbook: "Who will take the penalty" and "What kind of seeds will sprout". Because students usually don't have much contact with football, considering that the concept of "penalty" in the original textbook example 1 may be difficult for students to understand, I first use two familiar news to pave the way for penalty, and then enrich students' understanding of percentage through diversified training.

Teaching objectives:

1. Through the process of abstracting percentages from practical problems, I understand the necessity of introducing percentages and the meaning of percentages, so I can read and write percentages correctly.

2, through observation, comparison, induction and other learning methods, understand the meaning of percentage.

3. Let students realize that mathematics is closely related to daily life and infiltrate ideological education in time.

Teaching focus:

Understand the meaning of percentage, and you will read and write percentage correctly.

Teaching difficulties:

The difference between percentage and fraction.

Teaching aid preparation:

courseware

Teaching process:

(1) The scene introduction is really interesting (3 minutes)

Students, the teacher likes playing basketball. Do you want to know who the teacher's favorite basketball star is? (Yao Ming) Yao Ming's shooting percentage in NBA, CBA and All-Star Game is 49.8%, 65. 1% and 52.9% respectively.

Students, do you know what these numbers are called? Seeing these figures, what percentage do you want to know? (Meaning, reading and writing, function, similarities and differences) Let's bring these questions into the math class, explore the percentage together and uncover its mystery. Do you have confidence? Writing on the blackboard: understanding of percentage

(2) I am serious about autonomous learning (20 minutes)

Longfeng primary school campus broadcast room looking for a reporter wearing a red scarf. Do you want to take part in the competition? But there are competitive requirements:

News 1: The fifth census shows that the population of China accounts for 20% of the world's population.

News 2: According to statistics, among the students with poor eyesight in China, primary school students account for 18%, junior high school students account for 49%, and senior high school students account for 64.2%.

News 3: In the school football match, the penalty kick caused controversy. The Flying Tigers got the chance to take the penalty kick, but they had no choice. The situation is as follows:

No.7 player: 20 penalty points 18.

No.3 player: penalty 10, score 7.

Player No.5: Penalty 100, 89 points.

According to the news given by the recruitment team: A, choose a piece of news that you are interested in and tell the meaning of percentage in the news.

B express his feelings about this news concisely in one sentence.

Tips for learning plan:

1, the news I chose is () (fill in the serial number)

I think the percentage in the news means ()%

3. My feeling is that

The teacher asked you to find a percentage in your life. How much did you find? Hold it up, look at it by yourself, look at each other, and find such a percentage. Is it hard to find? Where did you find it? How do you feel?

5. I will say: report a piece of information that I have collected with percentage, and describe the meaning of percentage with the phrase "who is who's percentage".

(3) I will do cooperative inquiry (8 minutes)

The students in this class are really doing well. You already know the meaning of percentage. Can you read and write percentages? I believe you can do it.

1, the cultivated land area in China accounts for about 7% of the world.

2. Uncle Li's income this year is 120% of that of last year.

The attendance rate of Class Five (3) today is 100%.

4. In his first year in NBA, Yao Ming shot 49.8%.

Last year, the water consumption of our school was 95% of that of the year before.

Tips for learning plan:

1, I can read and write percentage.

7% reading:

120% pronounced as:

100% pronounced as:

Forty-nine point eight percent writing:

Ninety-five percent of writing:

Percentage of free writing in 2.30 seconds. The teacher asked to write 10. I can express my completion in percentage.

I wrote a percentage, and the number written is ()% of the task, I found.

3. Compare whose eyes are the brightest.

The broadcast room of Longfeng Primary School is broadcasting an Olympic news: The Bird's Nest is the competition venue of the Olympic Games, covering an area of 26 square kilometers.

Reporter Li Li wrote: The bird's nest covers an area of 26/ 100 square kilometers.

Reporter Li Mei wrote: The bird's nest covers an area of 26% square kilometers.

Who is right and who is wrong? Discuss and communicate in groups. Why?

(4) I am excellent in the standard test (5 minutes)

1, have a glib tongue

(1) The results of the fifth national census show that at present, the male population accounts for about 52% of the total population in China, and the female population accounts for about 48% of the total population.

(2) The school attendance rate is 98% today.

(3)80% cotton and 20% polyester fiber

(4) 100% pure fruit juice

(5) In 2002, the urban greening coverage rate in Beijing was 40.6%.

Step 2 stand out

The (1) percentage represents the multiple relationship between two numbers. ()

(2) The denominator of the percentage is 100. ()

(3) Fractions with denominator of 100 are called percentages. ()

(4) A rope is 50% meters long ()

3. Idiom guessing

Kill two birds with one stone.

One in a hundred () is in the palm of your hand ()

Step 4 choose carefully

120% 100%6%90%

(1) Thanks to the mutual help of the whole class, the passing rate of this exam reached ().

(2) The speed of the car is that of the bus ().

(3) Since the implementation of saving activities, the school's electricity consumption has decreased this month compared with last month ().

(4) 3000 plants were planted in Yangcun, and 2700 plants survived, with a survival rate of ().

Summary: The red scarf recruitment team saw the wonderful performance of the students and agreed to recruit all the students in Class 503 as red scarf reporters.

(5) Summarize my decision after class (2 minutes)

Through the study of this course

(1) My satisfaction with my performance is ()%.

(2) I (very, a little, no) regret, so the degree of regret is ()%.

(3) In the future classroom performance, I will make ()% efforts!

(6), knowledge expansion, I will design (2 minutes)

I can design a pattern myself. The content of the pattern is (), and the whole pattern accounts for ()% of the whole pattern.