Activity objectives:

1. Let students understand the meaning of numbers and establish their digital consciousness through their perception and experience of specific numbers.

2. Through study and communication, students can gain the joy of success and cultivate the habit of learning from others and communicating with others.

Highlights and difficulties of the activity:

1, understand the meaning of 100 million, and establish a sense of numbers.

2, combined with the specific amount to get an intuitive feeling-1100 million.

Prepare teaching AIDS and learning tools:

1. Each student prepares a calculator and 100 grains of rice.

2. The teacher prepares: exercise books, five stopwatches, three scales, an electronic scale and a tape measure.

I. Introduction to the event:

1, Dialogue: Students, do you know how many people there are in China? So do you know how big 100 million is? Blackboard: How big is 100 million?

2. Write 1000000 and 100 on the blackboard. Then guide students to understand the size of 65.438+billion from the composition of numbers: 65.438+billion, 65.438+billion, 65.438+billion, 65.438+billion and 65.438+billion. ...

(Design intention: Use the students' existing life experience and knowledge to introduce 100 million yuan and review the composition of 100 million yuan. )

3. Do you want to figure out how big 100 million is by yourself?

Today we will carry out several activities to let the students feel "how big is 100 million".

(Design intention: connecting the preceding with the following, ask questions according to the trend, and stimulate students' interest in exploration. )

Second, carry out activities. (practical activities)

1. Announce the requirements of actual operation activities.

Our movable tools include: balance, electronic scale, stopwatch, tape measure, calculator, etc. Students work in groups, choose activity materials and determine the theme. According to the theme and requirements of the activity, the group leader will freely combine the members of the group, and then make a detailed division of labor to ensure that each member can participate in the activity.

Please record the statistical data of the activity in time and complete the corresponding analysis on the record sheet (design intent: guide students to compare the final data with the common data in life in the analysis to deepen their understanding. )

Event theme default value:

How thick is a hundred million pieces of paper?

/kloc-How big is the place where 0/100 million children stand hand in hand?

/kloc-how much does 0/100 million grain of rice weigh?

How much is 100 million words?

How long does it take to count 1 100 million?

How long does it take to count 1 100 million exercise books?

/kloc-How much does a 0/100 million coin weigh?

Activity plan and steps:

Activity group and activity plan

Step and Result Group 1

How thick is a hundred million pieces of paper? the second group

100000000000 children, how old is the third group?

1100,000 grains of rice have multiple fourth groups.

What is 1 100 million?

Step one:

Determination of the base number (completed by group cooperation) (teachers selectively) prepared 100 sheets of paper for students to measure the thickness, and the students measured:

100 sheets of paper are about 1 cm thick and stand at 1 m2. In order to be comfortable and natural, the number of children standing in 1 square meter is 1 gram meter.

1 g There are 53 films in Mi Yue. By referring to the description on the back cover, I know that there are 227,000 words of "100,000 Why" in five books.

Step two:

Reasoning calculation

(Under the guidance of the teacher, use a calculator)100000000 ÷100

= 1000000 cm

=10000m 10000000 \4

= 25 million square meters

= 2,500 hectares

=25 km2 1 gram meter 53 capsules

1000 grams of rice 53000 grains

100000000÷53000

≈1887kg

1887kg≈2≈ 10000000≈227000

≈440 (set)

(Design intent: Let students actually measure and feel the thickness of1000 sheets, and then realize the thickness of100000 sheets. Give full play to students' operational ability and cooperation ability. )

Results: 65438+ 100 million pieces of paper were about 10000 meters high. There are 4 people per square meter, and 65438+ billion children have to stand 25 square kilometers. 65438+ billion grains of rice weigh about 2 tons. A set of "100 thousand whys"

* * * 227,000 words, 440 episodes are enough for 65.438+0 billion words.

Third, communication and promotion.

Group report, according to the report, the teacher helps the students to build a three-dimensional model and feel how big 1 100 million is.

1. Guide students to compare the height of 1 100 million pieces of paper with the height of Mount Everest.

65438+ 100 million sheets of paper are about 10000 meters. The highest mountain in the world is Mount Everest, with an altitude of more than 8,800 meters. Therefore, 65438+ billion pieces of paper add up to be higher than Mount Everest.

2. Guide students to compare the area of 654.38 billion children's stations with the area of our town.

1 100 million children have to stand 25 square kilometers, and our school has a total area of 30 square kilometers. So 1 100 million children are still dissatisfied; To fill the whole school, you need more than 654.38 billion children.

Combine the pictures on page 2 1 of the textbook to educate students on population and resources.

3. Help students build a physical model of 65.438+0.3 billion grains of rice.

1 100 million grains of rice is about 2 tons. China has a population of/kloc-0.30 billion, and each person saves/kloc-0 per grain of rice every day. 1 day will save1.300 million grains of rice, about 26 tons. It will be transported by a truck with a load of 4 tons, and it will be transported seven times! Therefore, it is necessary to cherish grain, save medicine and grain, and benefit the country and the people.

4. Guide students to explore how long it will take to finish reading 100 million words.

If you read 5000 words every day for 365 days a year, 1 year can read 1 825,000 words, and it takes 1 825,000 words to read 1 billion words. In other words, if a person reads 5000 words every day, it will take 55 years to finish reading 654.38 billion words.

Educate students to read more books and study hard.

(Design intention: In class, teachers and students exchange experiences and understanding with each other, and it is the focus of this class to perceive how big 100 million is through the comparison of specific things. )

Fourth, raise awareness and sublimate emotions in activities.

Read the information below and say how you feel.

654.38 billion drops of water can be collected into about 3333 liters of water, which can hold four large water trucks.

1 100 million pieces of paper are stacked together, which is about 10000 meters high, which is higher than Mount Everest.

In recent years, China's wheat output has been stable at around 65438+ 100 million tons.

Xinmin Daily, February 26, 2004-The United Nations Food and Agriculture Organization announced on Wednesday that more than 6,543.8 billion chickens have been slaughtered in Asia where bird flu broke out.

In 200 1 year, the number of mobile phones in China has exceeded 1 100 million.

(Design intention: apply this specific amount of 100 million to real life, and consolidate students' mastery and flexible application of knowledge. )

Verb (abbreviation of verb) abstract

Teacher: Today, through some activities, we initially felt how big 100 million is. How big is a hundred million? Tell our family what we know in this class. Simply put, 1 100 million is a big number. If you use multiplication, a small number multiplied by 100 million will become a big number. If calculated by division, a large total divided by 1 100 million will become a small number. China's railway transportation density is the highest in the world, but the per capita railway length is the shortest in the world, which is not enough for a cigarette.

(Design intention: Through the negative comparison of 100 million yuan, highlight the national conditions of China, cultivate students' patriotic feelings and stimulate learning motivation. )

blackboard-writing design

How big is 100 million

1 billion: 10000000

1, 1 100 million sheets of paper 10000 meters high, higher than Mount Everest.

2, 1 100 million children can stand 25 square kilometers, which is equivalent to half the area of hengli town.

3. 1 100 million grains of rice weigh about 2 tons, and China saves 1 grain per person every day, which can save 26 tons.

If it is transported by a truck with a load of 4 tons, it will be transported seven times.

4, 100 million words will take a lifetime to read, if you read 5000 words a day.

Reflection after teaching:

The purpose of this lesson is to let students solve the problem of 654.38 billion yuan with what they have learned and feel how big it is in the process of solving the problem. Then, let the students do the activities by themselves. Before class, I made full preparations. Some students have prepared a certain amount of manuscript paper, some students have prepared rice grains, or a certain amount of 1 yuan coins ... In class, students are allowed to freely combine into activity groups according to what they have prepared, determine the research content and activity steps of each group, and conduct specific experiments. I let students think freely and communicate freely, which is done by group cooperation. Facts show that students' internal potential is great. Through experiments, they calculated that the height of 1 100 million pieces of paper exceeded 6000 meters; 1 100 million math books have an area of about 3 15 hectares; 1 100 million grains of rice weigh about 1 ton. Students calculate the results through experiments, but these results are abstract and unimaginable. I showed the data collected by students before class in time, and compared with the experimental results, the students could not help but sigh. 100 million pieces of paper piled up to the height of more than 30 Wangs Tiantan Peak; 1 100 million math books are as high as 74 Mount Everest ... Students intuitively feel the scale of 1 100 million. Throughout the class, I let students experiment, discover and explore, which really gave students a platform and space for independent activities.