1. 1 knowledge and skills:

1. Have a preliminary understanding of negative numbers in familiar life situations, can read and write positive and negative numbers correctly, and know that 0 is neither positive nor negative.

2. Learn to express some practical problems in daily life with negative numbers and experience the close relationship between mathematics and life.

1.2 process and method:

Experience the cognitive process of negative numbers and the methods of comparison and induction.

1.3 Emotional attitudes and values:

Feel the connection between mathematics and real life, stimulate learning interest, cultivate a good study habit of combining learning with thinking, and experience the logical beauty of the internal connection between mathematical knowledge.

Emphasis and difficulty in teaching

2. 1 teaching focus

Positive and negative numbers can be used to represent two quantities with opposite meanings in life.

2.2 Teaching difficulties

Solve practical problems in life with negative numbers.

teaching tool

multimedia courseware

teaching process

First, introduce games.

Students, let's play a game to relax today. This game is called. I'm against you? . Rules of the game: if the teacher says a word, please say the opposite.

1, look up (look down)

2. Go ahead 200 meters (go back 200 meters)

3. Elevator ascending15th floor (elevator descending15th floor).

4. Above zero 10 degrees Celsius (below zero 10 degrees Celsius)

It's good. Next, the teacher changed the rules of the game. The teacher shows you a picture (the courseware shows several pictures of the example 1 on page 2).

Second, the initial perception.

Teacher: Have you seen several pictures similar to the example 1 on page 2 before?

Health: Yes, when watching the weather forecast.

Teacher: China has a large area. At the same time, the temperature varies greatly in different regions. Look at this photo carefully. Look at these six cities. Can you read the weather conditions in these six cities?

Give an example of 1 scene diagram.

Students read it.

Third, understand negative numbers.

1, know the thermometer, and understand that positive and negative numbers are used to represent temperatures above zero and below zero.

Teacher: (The courseware shows thermometer) Do you know, students?

Health: A thermometer.

Teacher: Do you know what they mean? (Courseware shows℃, ℉)

Health:℃ means℃, pronounced as? Centigrade? .

Health: ℉ means.

Teacher: ℉ means Fahrenheit, pronounced as? Fahrenheit? . So what does our country use to measure the temperature?

Health: In China, the temperature is measured in degrees Celsius.

Teacher: How many degrees Celsius does a big grid represent? How many degrees Celsius does a cell represent?

Let the students know more about the thermometer through the courseware display, and let them know that the large cell represents 10 degrees Celsius and the small cell represents 2 degrees Celsius.

Teacher: How is 0 degrees Celsius stipulated? Do you know that?/You know what? Do you know that?/You know what?

Health: The freezing temperature of water is set at 0℃.

Yes, scientists set the freezing point of water at 0℃. Read: 0 degrees Celsius. Temperatures below 0℃ are called sub-zero temperatures and usually begin with a number? (minus sign)

Teacher: The temperature above zero is represented by a positive number, and the temperature below zero is represented by a negative number.

Teacher: What about above zero 10 degrees Celsius? : + 10℃- 10℃? :- 10℃

Health: above zero 10℃:+10℃; -10℃:-10℃.

2. Read the temperature displayed by the mercury column. (Courseware demonstration)

Show the temperature indicated by mercury column in the teacher's courseware and guide the students to read.

3. What information do you know from the weather forecast chart above?

For example, the highest temperature in Beijing is 5℃, and the lowest temperature is MINUS 5℃.

Teacher: Is Beijing -5℃ the same as 5℃? What does this mean?

Health: -5℃ is different from 5℃. -5℃ means 5℃ lower than zero and 5℃ higher than zero.

Health: -5℃ is different from 5℃. -5℃ is colder than zero, and 5℃ means hotter than zero.

The teacher concluded: 5℃ and -5℃ mean quantities with opposite meanings.

4. Read the weather temperature of each city in Example 1 correctly.

Teachers and students sum up together: When the temperature is higher than 0℃, do you want to add one before the number? +? Numbers or directly represented by numbers, read as zero? Centigrade. When the temperature is below 0℃, do you want to add an A before the number? -? Numbers, reading below zero? Centigrade. So +5℃ means 5℃ above zero, which is read as+3℃; -5℃ means minus 5℃, which is pronounced minus 3℃. (blackboard writing: +5℃ plus 3℃; -5℃-3℃)

Students independently complete the information table of example 1, and then talk about the meaning of each number with their deskmates.

Call the students to answer, and the teacher comments and summarizes.

5. Example 2 on page 3 of the textbook.

Teacher: Next, let's look at the picture of Example 2 on page 3. What does each number mean?

Health:? 2000? It means to deposit 2000 yuan.

Health:? -500? Say to consume 500 yuan.

Health:? - 132? It means expenditure 132 yuan.

Health:? 500? Said deposited in 500 yuan.

Teacher: Can you find words or mathematical symbols with opposite meanings? (Tip 2000.00 and +2000.00 represent the same meaning. )

Teacher: What do 500.00 and -500.00 mean here respectively?

Health: 500.00 means deposits in 500 yuan and -500.00 means expenditures in 500 yuan.

Students say the meaning of each number.

The teacher concluded: 500 and -500 represent quantities with opposite meanings.

Teacher: OK, class. Try to explain the meaning of other numbers in the picture.

Student exchange.

Step 6 think and summarize

Teachers guide students to compare Example 1 with Example 2, and find out what they have in common.

Teacher: student comparison example 1 and example 2. Do they have anything in common?

Students discuss and report in groups. Tip: In case 1 and case 2, there are two numbers to represent two opposite quantities? Above zero and below zero, expenditure and income.

What are 7 and 0?

Teacher: What do we think is the height of sea level?

Health: as 0.

Teacher: (Courseware demonstration) Use (+several or several) to indicate that it is above sea level, for example, use (-several) to indicate that +5000m is below sea level, for example, -2000m.

Think of sea level 0 as the dividing line between positive and negative numbers.

Teacher: (courseware demonstration) Mount Everest is 8844.43 meters above sea level. What do you mean?

Health: the record is +8844.43 meters.

Teacher: The elevation of Turpan Basin is 155 meters. What do you mean?

Health: recorded as-155 meters.

The courseware shows a little knowledge: sea level, considering the name and thinking, is the sea level. It is used to measure the height of the ground, also known as altitude. All geodesy and marks in China start from the datum point of the Yellow Sea, and any elevation above sea level is the datum point relative to the Yellow Sea.

Through the understanding of sea level, 0 on the thermometer is like a dividing line, which separates positive numbers from negative numbers, so 0 is neither positive nor negative. )

Summary: In order to represent two quantities with opposite meanings, a new number appears here:-16, -500. Numbers like-16, -500, -3 and -0.4 are called negative numbers. -Pronunciation is minus three eighths.

And the number16,2000,6.3 that I learned before is called positive number. Can it be added before a positive number? +? Numbers, such as+16,+,+6.3 and so on. +? Number). +6.3 is pronounced 6.3.

Teacher: 0 is like a dividing line, which separates positive numbers from negative numbers. 0 is neither positive nor negative.

8. do this

The courseware shows the topic:

(1), represented by positive and negative numbers.

① Above zero 12.5 degrees Celsius is expressed as _ _ _ _ _, (+12.5 degrees Celsius).

3.5 degrees Celsius below zero is expressed as: _ _ _ _ _ _. (-3.5 ℃)

② There is a pit somewhere in Guangxi.

Pit mouth elevation 125m, expressed by _ _ _ _ _, (+125).

The bottom of the pit is m below the sea level, which is expressed as _ _ _ _ _ _. (? 100)

(2) Read it first, then discuss: How to classify these figures by observation?

Students discuss at the same table, and the teacher reports by name.

9. Teachers guide students to summarize: Numbers can be divided into positive numbers, zero numbers and negative numbers. Positive numbers include positive integers, positive fractions and positive decimals, while negative numbers include negative integers, negative fractions and negative decimals. 0 is neither positive nor negative. It is the dividing point between positive and negative numbers.

Can I write before a positive number? +? But I don't usually write, and what about the negative number in front? -? Must write. Can you read before a positive number? Positive? , but don't watch it at ordinary times (if there is? +? Number required reading), the number before the negative number? Negative? Must read.

Fourth, integrate into life.

Teacher: Negative numbers are still widely used in our production and life. Let's walk into life together and feel the close connection between numbers and life. The courseware shows the test topics:

1. You know that the temperature when water boils is _ _ _ _. The temperature when water freezes is _ _ _ _. The lowest temperature on the surface of the earth is _ _ _ _ _ _. The lowest temperature on the surface of the moon is _ _ _ _ _ _. ( 100℃,0℃, -88.3 ℃, - 183℃)

Step 2 do this

Victory 5 is marked as _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. (+5 games, plus 5 games)

Input 3 is marked as _ _ _ _ _ _ _ _ _, which is pronounced as _ _ _ _ _ _ _. (-3 games, negative 3 games)

/kloc-the income of 0/00 yuan is recorded as _ _ _ _ _ _ _ _ _ _ _. (+100 yuan, plus one hundred yuan)

Expenditure within 200 yuan is recorded as _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. (-200 yuan, negative 200 yuan)

Students talk and say their names.

3. which two buttons should I press when my uncle goes to the fifth floor for a meeting and my aunt goes to the second floor underground to get the car?

Students talk and say their names.

There is an intelligence contest in three classes of grade six. Answer a question correctly and get 10; Answer a wrong question, get 10; If you don't answer, 0 points. According to the results of three classes, talk about their answers.

Students talk and say their names.

5. Will you use positive and negative numbers to represent the altitude of the following places?

(1), Huashan is 2000m above sea level, and it is recorded as (+2000m).

(2) The Dead Sea is 392m below sea level, which is recorded as (-392m).

Students talk and say their names.

6. I can judge right from wrong

(1) Any negative number is less than a positive number. (? )

(2) A number is either positive or negative. (? )

(3) because? 4? Not in the front? +? Number, so? 4? Is not a positive number. (? )

(4) 5 people get on the bus? +5 people? , the four people get off? Four people? . ( ? )

(5) Positive numbers are all greater than 0, and negative numbers are all less than 0. (? )

(6) The temperature indicated by ゜ +5゜C is as high as that indicated by+5 C. (? )

7. Brief communication

Teacher: Have you seen negative numbers anywhere else?

Health: It's on the household income and expenditure account book.

Health: the freezing room temperature of the refrigerator.

Health: the altitude shown on the map.

Verb (abbreviation for verb) consolidation exercise

1, textbook page 4? Do it. Question 1.

Students independently read -3℃ and-18℃, and think about which temperature is lower in Beijing or Harbin according to the questions.

The teacher called the roll to answer.

2. Page 4 of the textbook? Do it. Question 2.

Students answer in turn in groups, and teachers revise collectively.

The teacher emphasized that 0 is neither positive nor negative.

Summary after class

Teacher: What have you gained from learning this lesson?

Teacher: In this class, we got to know positive numbers and negative numbers together. In our life, above and below zero emittance, above and below sea level, score and loss have opposite meanings, and we can all use positive and negative numbers to express them.

Write on the blackboard.

Identify negative numbers

+5 degrees Celsius plus 3 degrees Celsius -5 degrees Celsius minus 3 degrees Celsius

Five-three-five-three

Three eighths-

Negative three eighths

0 is neither positive nor negative.

Negative number teaching plan (2) teaching objectives

Learn the basic properties of negative numbers and use them to solve problems.

Emphasis and difficulty in teaching

Solving problems by using the properties of negative numbers

teaching process

negative number

course content

People's Education Edition, Mathematics, a Standard Experimental Textbook for Compulsory Education Curriculum, Volume II of Grade 6, pages 2-4, examples 1 and 2.

Teaching objectives

1. Guide students to know negative numbers in familiar life situations and read and write positive numbers and negative numbers correctly; Know that 0 is neither positive nor negative.

2. Make students learn to express some practical problems in daily life with negative numbers and experience the connection between mathematics and life.

3. Carry out patriotic education for students in combination with negative history; Cultivate students' good mathematics emotion and attitude.

Emphasis and difficulty in teaching

The meaning of negative numbers.

teaching process

First, stimulate the introduction of interest

Introduce the new lesson with the theme song "Big Head Son and Little Head Dad".

Second, the teaching of new knowledge

1. quantities with opposite meanings.

(1) Understand two quantities with opposite meanings and introduce them with examples.

Teacher: Big head son is a very clever boy. After he learned the use of thermometer in science class, he immediately began to practice with his father when he got home.

Show the theme map of indoor and outdoor temperature.

It is pointed out that the indoor temperature is above zero 16℃ and the outdoor temperature is below zero 16℃, which have different meanings. (blackboard writing: above zero 16℃, below zero 16℃)

The teacher pointed out that above zero 16℃ and below zero 16℃ are two opposite quantities, and asked the students to give such examples in life and communicate in groups.

When reporting, the teacher has the choice of writing on the blackboard, and further points out that these are two quantities with opposite meanings.

(2) Try to create symbols and unify them.

Teacher: In the study just now, we used words to express two opposite meanings. If the words are removed, can we only use the numbers we have learned to express this opposite meaning?

In order to stimulate students' desire to create symbols and use them uniformly? + -? Express two opposite meanings.

2. Teach yourself the textbook and know the positive and negative numbers.

(1) Show self-study skills and guide students to learn textbooks by themselves.

Teacher: This symbol is no longer an operation symbol here, so you can't read it any more? Add and subtract? How should I read it? What are the numbers generated in this way? Textbooks are our best teachers. Please teach yourself the textbook with questions.

Show self-study skills, and let students teach themselves textbooks with questions.

(2) Reporting and communication.

① Understand how negative numbers are generated.

(2) Illustrate what positive numbers and negative numbers are, read them correctly, and illustrate where negative numbers have been seen.

Summary after class

③ Understand why 0 is neither positive nor negative.

3. Feel the history of negative numbers in combination with the learning process of this lesson.

Teacher: China people first produced negative numbers according to business needs. These examples we cited reflect this need. The ancients experienced many ways to create negative numbers, such as using colors in the second picture, using diagonal lines in the third picture, and expressing negative numbers in various forms abroad. Just now, we also went through this creative process, and finally formed the present form of expressing two opposite meanings with positive and negative numbers.

After the teacher's introduction, the students tell their feelings.