Jiangsu Education Press Primary School Mathematics Textbook XI, page 1 12: Practical activity "calculating its popularization rate".

[Activity objective]

1, so that students can use percentage knowledge to calculate the telephone and computer penetration rate of classmates' families, and simply compare, analyze and estimate the development trend, thus cultivating students' thinking ability and practical ability of comparative analysis.

2. Let students understand and feel the connection between mathematics and life, and gradually cultivate students' awareness and ability to apply mathematics knowledge.

3. Make students realize that the living standards of our people have improved rapidly after the reform and opening up, and enhance their thoughts and feelings of loving the socialist motherland.

Scene 1:

Teacher: Students, last night, the teacher wanted to inform everyone to bring calculators today. What can I do?

Health 1: You can call our home phone or mom and dad's cell phone.

Health 2: Send an email. My email is ...

Health 3: You only need to notify one person, and then I will notify five people, and the notified students will notify five students respectively, quickly and well.

Teacher: Many students in our class have telephones at home, and many have computers. Today, let's investigate who installed a telephone and bought a computer in our class.

Student 1: Teacher, don't investigate. I have the home phone number of the whole class here. 0/00% of the students in our class/kloc have telephones at home.

Student 2: You can find out which students have mobile phones or PHS at home to facilitate contact.

Teacher: (born in 1) Li XX, you are a man of heart. 100% of students have telephones at home, so it can be said that the telephone penetration rate is 100%. In our life, "permeability" is often calculated and used. In this lesson, we will calculate some permeability. Such as household mobile phone penetration rate and computer penetration rate.

[Comment] In this link, it will be of far-reaching significance to change the original teaching presupposition in time and give students a chance to show.

Scenario 2:

Students report the percentage results of statistics and calculations after grouping statistics.

Teacher: What is the penetration rate of my classmate's home mobile phone? How to calculate it?

Student 1: The mobile phone penetration rate is 96.6%, which means finding out what percentage of 58 families in the class have mobile phones.

Health 2: Teacher, I think we should say "about 96.6%".

Student 3: There are 39 families with computers in our class, and the penetration rate is about 67.2%.

Teacher: Can you calculate the telephone and computer penetration rate in this area according to the calculation results?

Health 1: I think the fixed-line telephone penetration rate of Nantong residents is close to 100%, the mobile phone penetration rate is about 95%, and the computer penetration rate is even lower, maybe 60%.

Health 2: I don't totally agree with you. We can't think that my classmate's home phone penetration rate is 100%, but Nantong residents' fixed phone penetration rate is close to 100%. You should take into account that there are still relatively poor places in Nantong. It should be said that the telephone penetration rate in Xuetian area is close to 100%.

S3: I agree with my classmate just now. Because most of my classmates live in Xuetian Xincun, if we want to investigate the fixed telephone penetration rate of Nantong residents, we should also go to other schools or Xincun to investigate.

Teacher: You are so thoughtful. How do you think we should investigate?

S3: I think it is accurate to determine a school or a new village in Nantong.

Teacher: That is to say, to calculate the estimated penetration rate, we should consider the economic situation of Nantong students' families.

[Comment] In this process, let the students show their truest thoughts to the fullest. No matter what the teacher wants him to say, it depends on whether my own views are accurate, unique and have my own personality. Teachers' encouragement and feedback "are conducive to creating the general conditions of activities-psychological safety and psychological freedom". Only in a psychologically safe environment can students boldly guess, question and express different opinions.

Scenario 3:

Teacher: What did you learn from this practice?

Health 1: It is known that after investigation and statistics, the prevalence rate of something can be known.

Health 2: I know that the popularity of computers is lower than that of telephones. We can feed back the survey results to computer companies and ask them to strengthen publicity and engage in more promotional activities.

S3: I know the statistics and percentages we studied are very useful.

Health 4: I think the living standard has improved, because my grandmother said that people used to look forward to such a good life as "upstairs and downstairs, with lights and telephones". Now we have not only lights and telephones, but also computers, and some people have private cars!

Health 5: ...

Teacher: What other meaningful investigation activities can we carry out?

Student 1: Many students in our class wear glasses. We can investigate the myopia rate in our class or the whole school to attract everyone's attention.

Student 2: I often see some students buying snacks at the stalls outside the school. I want to investigate the use of students' pocket money every month and how much money I have to buy school supplies and snacks.

S3: I wonder how many people still know about Zhang Side. Now many students know "Little Swallow" Zhao Wei, but don't know the hero Zhang Side.

Health 4: I want to investigate how many poor families there are in Nantong.

Health 5: ...

[Analysis] Students are the main body of the classroom and provide students with opportunities to participate. Teachers will never replace what students can operate and realize. Do not deliberately ask students to think like teachers; Do not deliberately ask individual students to give answers that can represent the whole class. Mathematics teaching should cultivate students' ability to find, ask, analyze and solve problems.

One of the basic concepts of mathematics curriculum standards is that "students' mathematics learning content should be realistic, meaningful and challenging, and these contents should be conducive to students' active observation, experiment, guess, verification, reasoning and communication." This practical activity class is arranged after students have preliminarily learned the meaning and application of percentage. The content of the activity comes from life, which can make students feel that mathematics is around, and mathematics is inseparable from life. The thinking of primary school students is gradually changing from concrete thinking to abstract thinking, but this does not mean that students do not need concrete thinking. Mathematics comes from life, but it is higher than life, and it has certain abstraction and logic. Hua, a famous mathematician, said: the universe is big, the particles are small, the rockets are fast, the chemical industry is clever, the earth is changing, and the daily use is complex, so mathematics is needed everywhere.

For students, if they always accept and study passively like adults, they will feel that learning mathematics is very boring, and their initiative, enthusiasm and creativity will gradually fall asleep and gradually alienate mathematics. Practical activities make students change from passive to active and from repetition to innovation, which is conducive to the development of students' personality and the cultivation of students' innovative consciousness and practical ability. Vivid and interesting practical experience makes students feel that mathematics is not boring. Let children explore mathematics in their own world in the way they like, and experience and enjoy mathematics in the process of exploration. Mathematics is alive and full of vitality when it is closely combined with children's real life.

Encourage students to gain in their own words, not just repeat the teacher's teaching. Facing students with vivid life and flexible personality, teachers should pay more attention to students' emotions and attitudes in mathematics activities, and should give positive evaluation, so as to provide students with a stage to freely express their thoughts and opinions and realize their own thinking leap, help students know themselves and establish self-confidence in learning. Teachers should become appreciators, supporters and leaders in students' learning process.

How to correctly understand mathematical practice, how to do it well and how to present it are urgent problems for us to solve. I think this is extremely fresh and challenging. In the process of exploration, I learned that practical activities are the concrete expression of "doing mathematics", and it is a new curriculum form with the goal of solving a practical mathematical problem and the core of arousing students' mathematical thinking, so that students can understand, master and apply mathematics in the process of solving specific problems. Practice is a kind of inquiry learning, and students have to go through a complete process of collecting information, processing information and drawing conclusions. The enlightenment left by this lesson is that students will give you a surprise when you really put the concept of the new curriculum into concrete teaching behavior!