I. Significance:

Application in real life: Proportion widely exists in daily life and practical problems. For example, the proportion of ingredients in recipes, the proportion of maps in finance, interest rates, exchange rates, etc. all involve proportional relations.

Mathematical modeling and problem solving: In mathematical modeling, proportion is an important way to describe the relationship between things. Many practical problems can be solved by proportion, such as currency exchange, length comparison, graphic similarity and so on.

Usage of proportion: As a tool, proportion is widely used in statistics, commerce, scientific research and other fields. It helps to understand and interpret data, trends and changes.

Second, the basic nature:

Proportional relationship: if two proportions are equal, it is said to be proportional. For example, the ratio of two scales is equal, for example, a/b=c/d, then they are equal.

Multiplicity relation: two numbers in a proportion become multiples. For example, a is n times that of b, which can be written as a=nb.

Inverse relationship: if two quantities are inversely proportional, one increases and the other decreases, so that their product remains unchanged, then they are inversely proportional.

Change of proportion: in a proportion, if the multiple of one quantity increases, the other quantity also increases by the same multiple, and the proportion remains unchanged.

Third, the application of mathematics:

Calculation of proportion: cross multiplication is used to solve the unknown item of proportion, and proportional relation is used to solve various practical problems.

Graphic similarity: proportion plays an important role in graphic similarity, and there is a specific proportional relationship among the side length, area and volume of similar graphics.

Percentage and ratio: percentage is a special ratio, which is often used to express ratio, which is very helpful for comparing and describing data changes.

Proportion is an important concept in the mathematics curriculum of grade one and grade six. Understanding and mastering the basic nature and application of proportion can help students better understand and solve problems in daily life and lay a solid foundation for further learning more advanced mathematical concepts.