1, the idea of transformation is to transform a practical problem into a mathematical problem and a more complicated problem into a simpler one;

2. The idea of combining numbers and shapes is to make full use of "shapes" to vividly express certain quantitative relations, that is, to help students understand the quantitative relations correctly by making some graphs such as line segments, tree diagrams, rectangular area diagrams or set diagrams, so as to make the questions concise and intuitive;

3. The idea of transformation is the idea of transforming from one form to another, such as the same solution transformation in solving equations, the proposition equivalence transformation in laws and formulas, the equal product transformation in geometric forms, and the inverse transformation in understanding mathematical problems.

4. The idea of combination is to group the studied objects reasonably and solve all possible situations without repetition or omission.