The surface of the object, let's enjoy it together (courseware demonstration)

There are too many surfaces on objects, aren't there? There are many objects around us. Let's find and touch their surfaces together, shall we? ?

Let's start with our closest friend's math book! Touch the cover of the math book, and then touch the desk, which is bigger? Which is smaller? What about the surface bigger than the desktop? (On the blackboard) What's bigger? What are the edges smaller than the cover of a math book? The sides of the pencil box (emphasizing six sides) are smaller? Rubber, etc ...

3. Who wants to compete with the teacher? What did you find? ?

In the kingdom of mathematics, all the surfaces we have just touched and seen have a new name-area. Remember the first keyword. (blackboard writing:? The surface of objects is their area. Let's talk about area: the size of the cover of a math book is the area of the cover. No, the math book has six sides, and the size of each side is different, so the cover can only be the area of the cover. Similarly, the size of the class desktop can only be the area of the desktop, and the surfaces of objects such as glass, floor and blackboard are called their areas. ?

(2) Know the area of the closed graph. ?

Regions seem to be everywhere in our lives, but each region has its definite size. ?

1. This is a cube. How many sides does it have? What is the size of each face? So the six faces of the cube have the same area. We drew one of them on the blackboard. What has this face become? It turns out that the size of this surface is the size of a square. What is the area of that square? ?

2, draw a triangle, find the area, than the size. ? 3. Draw a corner and find the area. I can't find it. Why? ?

What kind of number is the area? What is a closed graph? There are also large and small closed graphics (the size of closed graphics is called its area) (blackboard writing)?

2, know the closed graphics (courseware)?

Teacher: The students spoke very well! Since we are more and more familiar with the area, who can describe what the area is? ?