1, to understand the meaning and basic properties of proportion, will be solution ratio.

2. Understanding the meaning of positive proportion and inverse proportion can help us find examples of positive proportion and inverse proportion in our life, and we can use the knowledge of proportion to solve simple practical problems.

3. Knowing the image with positive proportional relationship, you can draw an image on grid paper with coordinate system according to the given data with positive proportional relationship, and you can calculate or estimate the value of the other quantity in the image according to one of them.

If you know the scale, you will find the scale of the plan and the distance or actual distance on the map according to the scale.

5, understand the phenomenon of zoom in and out, can use the form of grid paper to zoom in or out simple graphics according to a certain proportion, and realize the similarity of graphics.

6. Infiltrate the thought of function, and let students be inspired by dialectical materialism.