1, direct debit method

It is direct analysis and reasoning. When conditions permit, we use relevant knowledge to directly analyze the problem, calculate the results after deduction, and finally make correct analysis and judgment. This is the most basic, commonly used and important method.

Applicable questions: this method is generally used in calculating multiple-choice questions and is also commonly used in other questions.

2. Inverse deduction method

Reverse deduction is reverse deduction or reverse substitution. The reverse deduction method is to use options (that is, multiple-choice options) to reverse the conditions, eliminate the options that contradict the conditions, and the ones that meet the conditions are the correct ones, or substitute one or several options in turn into the topic setting conditions for verification and analysis, and the ones that meet the topic setting conditions are the correct ones.

3. Counterexample method

If an option is a proposition, to exclude it or explain that the proposition is wrong, sometimes just give a counterexample. Counterexamples are usually some commonly used, simple but illustrative examples. If we pay due attention to accumulating different counterexamples related to various knowledge points when reviewing or doing problems, it may come in handy in the exam.

4. Special value method (special case method)

If the topic is a universal proposition, you can try to take one or several special situations and special values to verify which options are correct and which are wrong, or which options are likely to be correct or wrong, so as to make the right choice.

Applicable questions:

(1) When the conditions and conclusions are universal, take special cases to determine or exclude certain options;

(2) It is necessary to use counterexamples to prove that a conclusion that does not hold water or may not hold water is wrong;

(3) For some problems that are difficult to judge, assume that it is correct under special circumstances.

Step 5 reduce to absurdity

Among the four options of multiple-choice questions, if one option is assumed to be incorrect (or correct) and contradictions can be deduced, it means that the option is correct (or incorrect). When choosing which option to start with, you must analyze and judge according to the conditions of the topic, and sometimes you may need some intuition.

6. Combination of numbers and shapes

Draw the corresponding geometric figures according to the conditions, and analyze them by combining mathematical expressions and figures, so as to make correct judgments and choices. This method is often used in geometry-related multiple-choice questions.

7. Exclusion method

If four of the five options can be eliminated by one or more methods, then the remaining one is of course the correct option, or three of the five options can be eliminated first, and then the remaining two can be judged.