Tisch
Teaching objective: 1. Further understand the meaning of "increase by a few percent" or "decrease by a few percent" according to the actual situation, and deepen the understanding of the meaning of percentage.
2. It can solve the practical problem of "how many percent a number is more than a number" or "how many percent a number is less than a number" by drawing line segments.
3. Cultivate students' ability to solve practical problems and realize the close relationship between percentage and real life.
Teaching focus:
Understand the meaning of "increase by a few percent" or "decrease by a few percent".
Teaching difficulties:
It can solve the practical problem of "increasing by a few percent" or "decreasing by a few percent".
Teaching process:
First, the scene import reveals the theme.
Students, earth-shaking changes have taken place in our Zhuanghe in recent years. Since 1997, China railway has been speeding up on a large scale. The speed of a train used to be 180 kilometers per hour. After speeding up, the speed of this train has increased by 50%. How many kilometers does this train travel per hour now?
Today, let's study the problem of train speed-the application of percentage (2).
The blackboard writing project "Application of Percentage II"
Second, build a model.
1. Explore new knowledge
( 1)。 Guide students to think independently about how you want to solve this problem.
(2) Communicate your own thinking process with your peers.
(3) Group report and exchange information.
We can help to understand the meaning of the question by drawing line segments.
Please observe the line chart carefully and think, "What does it mean that the speed of this train has increased by 50%?" Let the students discuss in groups. Through observation, combined with the knowledge learned in the last lesson, we found that the speed of the train is now 50% higher than the original. So let's first calculate how many kilometers the train speed has increased.
① 180×50%=90 (km)
Then, let the students finish the next step independently.
②180+90 = 270km
So, is there any other way to solve this problem? Let the students discuss in groups. It can also be calculated that the original speed is regarded as 1( 100%) as a whole, and the current speed is calculated by 1+50%= 150%. Then, let the students finish the next step independently, 180× 150%=270 (km). (Comprehensive formula and step-by-step formula can be listed)
Please look at page 92 of the textbook "Practice", find a classmate to read the question and think about what "20%" means. Ask the students to say their names. A few percent is a few tenths, that is, dozens of percent. That is, ten percent is110, which is10%; Twenty percent is 2/ 10, which means twenty percent.
Third, explain the application and extension.
1. There were 160 students graduating from Chunlei Primary School last year, and the number of graduates this year increased by 15% compared with last year. How many students graduated this year? Let the students answer independently and deepen their understanding of the application of percentage.
2. The total area of downtown park is 24,000m2, of which buildings and roads account for 25% of the total area of the park, and the rest are green spaces. What is the total green area of downtown park?
Let the students answer independently, and then say two ways to solve problems, so as to cultivate students' ability to solve simple practical problems in various ways.
Fourth, summary.
What have you gained from learning this lesson?
Blackboard design:
The topic is in the middle of the blackboard, underlined on the left, and the problem-solving process in the middle.
extreme
Textbook analysis
Percentages are often used in daily life and productive labor, such as expressing the relationship between one quantity and another, calculating interest and taxes, designing and calculating discounts, etc. Using percentage to solve problems, you can use either formula calculation or formula equation to solve them. These are the teaching contents of this unit.
There are many teaching contents in the whole unit, and six examples, four exercises and the arrangement and practice of the whole unit are arranged, which are roughly divided into five sections.
Student analysis
Before learning this content, students have learned the definition of percentage, reading and writing, percentage and fraction, reciprocity of decimals, simple application of percentage, and solving simple percentage problems with equations. On this basis, the application of percentage is further studied.
course content
Primary School Mathematics Experiment Textbook (Beijing Normal University Edition) Grade 6 Volume 1 Unit 25-26.
Teaching objectives
1. Further understand the meaning of "increase by a few percent" or "decrease by a few percent" and deepen the understanding of the meaning of percentage.
2. It can solve the problem of "how much more than a certain number" or "how much more than a certain number"
Reduce the number by a few percent and increase the number of applications.
Learn the ability to solve practical problems, experience percentage and real life.
Close contact. Teaching focus
Understanding the meaning of "increase by a few percent" or "decrease by a few percent" can solve the practical problems about "increase by a few percent" or "decrease by a few percent".
training/teaching aid
Multimedia courseware.
teaching process
I. Introduction
1. There is an extraordinary scientist in our country-Yuan Longping. Do you know that?/You know what? If some students know, let them talk about it. )
2. He is a pioneer and leader in the field of hybrid rice research in China, the first scientist in the world who successfully used the heterosis of rice, and the international chief consultant of FAO, and is known as the "father of hybrid rice".
Because the yield of hybrid rice is much higher than that of ordinary rice, the planting area of hybrid rice in China is increasing year by year.
Second, the application of percentage
1. The percentage problem in life
In 2000, the rice planting area in a certain place was 200,000 hectares, and the planting area in 200 1 year increased by 25% compared with 2000. What is the planting area of 200 1 hybrid rice?
2. Line segment diagram
The teacher asked: Can you show the quantitative relationship between 2000 and 200 1 year with a line chart?
Students draw independently.
Show students' grades
Teacher evaluation
25% = 1/4
20 hectares
In 2000,
25%
200 1 year
3. Students answer questions independently
4. Intra-class communication
Scheme 1: 20 × 25% = 5 (hectare)
20+5 = 25 (hectare)
Option 2: 1+25% = 125%.
20 × 125% = 25 (hectare)
Third, give it a try.
1. Discount in life
Originally, during June 1 day, each amusement park package in 30 yuan was 20% off. How much can I save by buying such a set of packages?
2. Thinking: What does 20% discount mean?
Students are free to express their views.
Teacher evaluation
A 20% discount means that the current price is 80% of the original price.
3. Students answer independently and then communicate.
Scheme 1: 30 × 80% = 24 yuan.
30-24 = 6 (yuan)
Option 2: 30× (1-80%)
= 30 × 20 %
= 6 (yuan)
Fourth, practice.
1. Exercise textbook P26, 1 topic.
2. Practice the second question in the textbook P26
3. Practice the third question in the textbook P26
Verb (abbreviation of verb) course summary
What did you gain from today's study?
Tisso
course content
Primary School Mathematics Experiment Textbook (Beijing Normal University Edition) Grade 6 Volume 1 Unit 25-26.
Teaching objectives
1, further understand the meaning of "increase by a few percent" or "decrease by a few percent" and deepen the understanding of the meaning of percentage.
2, can solve "a few percent more than a number" or "than a.
Reduce the number by a few percent and increase the number of applications.
Learn the ability to solve practical problems, experience percentage and real life.
Close contact.
Teaching focus
Understanding the meaning of "increase by a few percent" or "decrease by a few percent" can solve the practical problems about "increase by a few percent" or "decrease by a few percent".
training/teaching aid
Multimedia courseware.
Preparation of learning tools
Teaching design
teaching process
Teaching process guidance
I. Introduction
1, there is a very scientist in our country-Yuan Longping, do you know? If some students know, let them talk about it. )
2. He is a pioneer and leader in the field of hybrid rice research in China, the first scientist in the world who successfully used the heterosis of rice, and the international chief consultant of FAO, and is known as the "father of hybrid rice".
3. Because the yield of hybrid rice is much higher than that of common rice, the planting area of hybrid rice in China is increasing year by year.
Second, the application of percentage
1, the percentage problem in life
In 2000, the rice planting area in a certain place was 200,000 hectares, and the planting area in 200 1 year increased by 25% compared with 2000. What is the planting area of 200 1 hybrid rice?
2. Line segment diagram
The teacher asked: can you show the quantitative relationship between 2000 and 200 1 year with a line chart?
Students draw independently. ※
Show students' grades. ※
Teacher evaluation ※
25%= 1/4
20 hectares
In 2000,
25%
200 1 year
3. Students can answer questions independently.
4. Intra-class communication
Scheme 1: 20×25%=5 (hectare)
20+5 = 25 (hectare)
Option 2: 1+25% = 125%.
20× 125%=25 (hectare)
Third, give it a try.
1, life discount
Originally, during June 1 day, each amusement park package in 30 yuan was 20% off. How much can I save by buying such a set of packages?
2. Thinking: What does 20% discount mean?
Students are free to express their views. ※
Teacher evaluation ※
20% off means that the current price is 20% off the original price. ※
3. Students answer independently and then communicate.
Scheme 1: 30×80%=24 yuan.
30-24 = 6 (yuan)
Option 2: 30× (1-80%)
=30×20%
=6 (yuan)
Fourth, practice.
1, textbook P26, exercise 1.
2. Practice the second question in the textbook P26
3. Practice the third question in the textbook P26
Verb (abbreviation of verb) course summary
What did you gain from today's study?
Starting from the situation provided by the textbook, the story of "You of Hybrid Rice" Yuan Longping is introduced, which leads to questions and stimulates students' interest in learning.
This paper introduces the planting situation of hybrid rice in a certain place in 2000 and 200 1 year, and leads to the practical problem of "how many percent more than one", so that students can draw inferences from others on the basis of existing knowledge to solve this problem.
Students can answer by themselves in various ways. The emphasis is on the exchange of methods.
Guide students to analyze how much money can be saved by asking for a purchase, and what to ask for first. Let students have a complete problem-solving idea.
Teaching reflection
This lesson focuses on how to guide students to use existing knowledge to solve new problems. The effect is good, students can get more mathematical information in communication, brainstorm and learn from others, not only learn a lot of problem-solving methods, but also learn how to communicate.