1. Four operations: addition, subtraction, multiplication and division are the basis of junior high school mathematics, and it is necessary to master the laws and methods of various operations.
2. Fractions and decimals: Fractions and decimals are important contents of primary school mathematics. You need to master addition, subtraction, multiplication, division, simplification and comparison of fractions, as well as reading, writing and four operations of decimals.
3. Percent: Percent is a way to express the proportional relationship, and it is necessary to master the methods of reading, writing and calculating percentage.
4. Geometry: Geometry is an important part of junior high school mathematics. It is necessary to master the names, properties and calculation methods of various geometric figures such as squares, rectangles, triangles and circles.
5. Data statistics: Data statistics is an important part of junior high school mathematics, and it is necessary to master the methods of data collection, collation and analysis, such as frequency, frequency and average.
6. Logical reasoning: Logical reasoning is an important part of junior high school mathematics, and it is necessary to master some basic logical reasoning methods and thinking skills, such as induction, deduction and analogy.
7. Problem-solving: Problem-solving is an important part of junior high school mathematics, and it needs to cultivate the ability to solve practical problems, including analyzing problems, putting forward hypotheses, verifying hypotheses and drawing conclusions.
The above are some key knowledge of junior high school mathematics. Students should pay attention to the consolidation and understanding of basic knowledge in the process of preparing for the exam, and at the same time do more related exercises and simulation questions to improve their problem-solving ability and test-taking ability.