Teaching design of "hectare, square kilometer" (1)
Teaching content:
Teaching objectives:
1, combined with the specific situation of solving the problem, realize the necessity of area unit conversion and the conversion relationship between area units.
2. Know the area units such as hectares and square kilometers.
3. Simple area unit conversion can be carried out to solve some simple practical problems.
Teaching emphasis: Experience the actual size of 1 hectare and 1 square kilometer, and find the progress rate between square kilometer and hectare. Teaching difficulties: correctly establish the expressions of 1 hectare and 1 square kilometer.
Activity preparation:
1. If it is used to measure a large area of land, it is easier to guide students to find out independently by observing and comparing.
2. Make students further experience the fun of solving problems and improve the level of problem-solving strategies.
Activity flow:
First, review and pave the way
1. Fill in the appropriate area units in brackets.
(1) The area of a bank card is about 40 ().
(2) The cover area of a math book is about 2 ().
The area of our classroom is about 50 square meters.
(4) The track and field area of our school is about 1 ().
2. What area units have we learned? Talk with reality.
Second, reveal the topic
Area units are widely used in production and life. Before this, students have learned and mastered smaller area units such as square centimeter, square decimeter and square meter. In production and life, it is often necessary to measure the area of larger graphics. For example, a forestry bureau wants to green the local desert area. The green area is a rectangle, 5 kilometers long and 4 kilometers wide. What is its area? Student column calculation, 5000? 40 million = 20 million square meters, that is, the area is 20 million square meters. It is inconvenient to express this big number with the learned area unit square meter. How to solve this problem? This is what we will learn in this class. A unit of area greater than one square meter? Hectares? With what? Square kilometers? .
Activity perception 1 hectare.
1. How big do you think 1 hectare is? Please guess with your imagination.
2. The teacher pointed out that the square (ground) with a side length of 100 meters has an area of 1 hectare. Calculate: How many square meters is 1 hectare? (Blackboard: 1 hectare = 10000 square meters) A hectare is a much larger area unit than a square meter.
How big is 3 or 2 hectares? What about 5 hectares?
How big is a square with a side length of 100 meter? Look for examples from everyday life.
5. Show the venue with a side length of 50 meters.
(1) Is there 1 hectare in this square? How do you judge?
(2) 1 hectare How many places are there? How would you put them together?
(3) display various spellings.
6. Show a picture with a side length of 10 meter (several students are holding hands for the side length).
(1) How big is this square?
(2) 1 hectare How many places are there? How would you put them together?
(3) display various spellings.
7. Can you judge how big our whole school is? How do you judge? How much is this area 1 hectare? What is the area of our classroom? How many classrooms have an area of about 1 hectare?
8. Is there a place around our school the size of 1 hectare? Can you give me an example?
Summary: What method did you use in the evaluation?
(Design intent: Through various activities, let students fully perceive the size of 1 hectare and form the appearance of 1 hectare. )
Fourth, think about it. How big is 1 square kilometer?
1 is a square with a side length of 1000m and an area of 1 km2. It covers an area larger than two Tiananmen Square.
2. What is the relationship between square kilometers and square meters and hectares? How many square meters is 1 square kilometer? How many hectares is it? Students convert area units. It is concluded that:1km2 =1million m2; 1 hectare =10000m2; 1 km2 = 100 hectare
The area of Tiananmen Square is 40 hectares, and 1 square kilometer is equivalent to the area of several Tiananmen Square. Its area is bigger than two Tiananmen Square, which is equivalent to the area of two Tiananmen Square.
The second part of the teaching design of "hectare, square kilometer"
Teaching objectives
1, so that students can know the commonly used land area unit hectare; Through actual observation and calculation, the actual scale of 1 hectare is realized; Knowing 1 hectare = 10000 square meters, we can simply convert units.
2. Let students use calculators and apply the knowledge of area formula and area unit conversion of plane graphics to solve some simple practical problems.
3. Make students further understand the relationship between mathematics and life in learning activities, and cultivate the ability of cooperative learning.
Important and difficult
Know 1 hectare = 10000 square meters, and then do simple unit conversion to realize the actual size of 1 hectare.
Teaching preparation courseware
teaching process
First, create a situation and introduce hectares
1, Dialogue: Students, what units of area have we learned? (Ask the students to draw the dimensions of 1 cm2, 1 cm2 and 1 m2. )
Now, please have a look and think about it. What unit should I fill in below?
Small keys on the computer keyboard, with an area of about 1 ()
The cover area of this math book is about 4 ()
The area of this classroom is about 50 square meters.
The area of a basketball court is about 200 square meters.
Question: Has anyone in our class been to Jinji Lake in Suzhou Industrial Park? Is it big? Do you know the area of Jinji Lake? Students estimate the area, and then the courseware presents: Jinji Lake has a total area of 740 hectares.
2. Exposed topic: When measuring the land area, it is usually in hectares. (Blackboard: the letter symbol of hectare is: ha) Today we are going to learn the new area unit hectare. How big is 1 hectare? How many square meters is its forward speed? Where can I find life 1 hectare?
Second, independent research, understanding hectares
1, understand the meaning of 1 hectare.
Dialogue: The area units we have learned before are all determined according to the square area with a certain side length. For example, 1cm 2 is a square area with a side length of1cm;
1 square decimeter is the square area with side length of 1 decimeter;
1 m2 is a square area with a side length of 1 m;
1 hectare: it is a square area with a side length of100m.
/kloc-How long is 0/00 meter? Can we talk about it in combination with reality? Imagine how big is a square land with a side length of 100 meter?
It is pointed out that such a large square area is 1 hectare. How many square meters is 1 hectare? Do math independently first, then communicate with your deskmate. It is concluded that: 1 hectare = 10000 square meters.
2. Experience the actual scale of 1 hectare.
Q: We must know 1 hectare. Let's actually feel it, shall we
(1) (Come to the playground) Let 28 students form a square hand in hand, ask for an estimate of the square area, and then ask for an estimate of how many such squares are 1 hectare.
(2) Let's calculate the square area in front of our class.
One side of the playground is about 100 meters long, and the adjacent side is about 30 meters long. Calculation:
100? 30 = 3000m2 10000? 1900? 3 (pieces) (calculated by calculator)
About three such playgrounds in our school can have 1 hectare. Imagine how big it is.
Question: We know that the area of our classroom is about 50 square meters, and the area of two classrooms is 100 square meters. 1 hectare How many classrooms are there? Can you imagine?
Where else can you find 1 hectare in your life?
3. Perform unit conversion.
Question: We already know that 1 hectare = 10000 square meters. Can you solve the following problems? Can I see it? Try it? Please use a calculator to calculate the problems in the book. Parallelogram vegetable field, base 250m, height 160m. How many square meters is this vegetable field? How many hectares? )
After completion, students are required to communicate with their classmates the solution process and the method of unit conversion.
Summary: When rewriting the quantity in square meters into the quantity in hectares, you can divide the original number by 10000, or directly shift the decimal point of the original number by four places to the left.
Step 4 consolidate the exercises
P93？ Practice? Questions 3-5.
Let the students calculate independently first, and then discuss whether the area of this football field is 1 hectare.
Third, go into life and solve problems.
1, ha? Information conference?
Known? Garden of ten thousand gardens? The so-called Yuanmingyuan, with a total area of 3.5 million square meters, is () hectares; Dunhuang Mogao grottoes are called? Art treasures? The murals in the grottoes are amazing to the world, with a total area of about 5 hectares and a contract area of () square meters. But they were all destroyed by imperialism.
What do you think after reading these two questions?
2, the developer's advertising
A new community has just been built in a city. Congcong went to see the house with his father and went to the door of the community to see a billboard:
Xiaoqujian steet
This community has an elegant environment and pleasant scenery, right? Demonstration community of urban greening. Covering an area of 12 hectare, including public facilities such as houses, children's playgrounds, gymnasiums for the elderly, tennis courts and roads, covering an area of10.5 hectare, with a green area of 5 hectares.
Congcong walked around the community and found 75 new residential buildings in the community. Cong Cong estimated that each building is about 80m long and10m wide. Please work it out with Congcong. Is the advertisement of real estate enterprises true?
Fourth, the class summary:
Dialogue: What did we learn today? What did you gain from today's study? Is there a problem?
Reflections on the teaching of hectares and square kilometers
According to students' existing life experience and actual cognitive level, different learning activities are arranged according to their understanding of hectares and square kilometers, reflecting different teaching objectives. Knowing hectares not only enables students to understand its meaning, but also enables students to experience the actual size of 1 hectare through activities such as observation, calculation, reasoning and imagination. For square kilometers, the key point is to let students know its meaning, explore the ratio between square kilometers and square meters and hectares, and learn to make simple conversion. When teaching, let students experience the actual size of 1 hectare through outdoor activities. For example, by observing the size of a playground with an area close to 1 hectare, we can directly perceive the size of 1 hectare; By observing the size of 100 square meters, we can indirectly perceive the size of 1 hectare through calculation and imagination; By choosing suitable land area units in specific situations, the perception will be further enriched, and the representation of the actual scale of 1 hectare will be gradually clear. Know square kilometers, and let students know that square kilometers are commonly used units for measuring and calculating large areas of land through relevant pictures and examples.
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