Definition and properties of 1. ratio: introduce what is ratio, how to define it and its properties. For example, when the first and second terms of the ratio are multiplied or divided by a non-zero number, the ratio remains unchanged.

2. Application of comparison: explain how to use the concept of comparison to solve practical problems, such as shopping, investment, engineering design, etc.

3. The concept of proportion: introduce what proportion is, how to define it, and the nature of proportion, for example, the product of two external terms equals the product of two internal terms.

4. Application of proportion: explain how to use the concept of proportion to solve practical problems, such as map drawing and financial calculation.

5. Difference between ratio and proportion: Compare the definition, nature and application of comparison and proportion, and let students know the difference between them.

6. Math games: design some math games related to ratio and proportion to increase students' interest in this part.

7. Mathematical stories: Share some mathematical stories related to ratio and proportion, such as how to discover the concept of ratio and how to apply the knowledge of ratio to solve practical problems.

8. Math puzzles: design some math puzzles related to ratio and proportion, let students think and solve them, and increase their understanding of this part.

9. Mathematical Proverbs: Share some mathematical proverbs related to ratios and proportions, such as "Birds of a feather flock together" and "Comparison is the key to understanding things" to help students understand the importance of ratios and proportions in their lives.

10, math exercises: design some math exercises related to ratio and proportion, let students practice and deepen their mastery of this part.

Application fields of ratio:

1. Shopping: When shopping, we can choose the most suitable commodity by comparing the prices and performance of different commodities. For example, we can choose a cost-effective TV by comparing the price, screen size and definition of different brands and models.

2. Engineering design: In engineering design, we need to calculate the proportional relationship between the weight and bearing capacity of each part according to different materials and structures to ensure the safety and stability of the project.

3. Chemical analysis: In chemical analysis, we need to analyze the proportional relationship between different substances. For example, we can determine the proportional relationship between different elements by analyzing their contents in different samples.

4. Statistics: In statistics, we need to use the concept of ratio to analyze data. For example, we can compare the data of different years and regions and analyze the proportional relationship and changing trend between them.

5. Daily life: In daily life, we often use the concept of ratio. For example, we can choose a washing machine suitable for our family by comparing the price and performance of different brands and models of washing machines.