Because the answer to multiple-choice questions is one of the four options, there must be only one correct answer, so we can use the exclusion method to exclude the answer that is easy to judge as wrong from the four options, so the remaining one is naturally the correct answer.

Method 2: The method of assigning special values.

That is, according to the conditions in the topic, select special values that meet the conditions or make special graphics for calculation and reasoning. When solving problems with special value method, we should pay attention to selecting values that meet the conditions and are easy to calculate.

Method 3: directly observe or get the results by guessing and measuring.

This method is often used to explore the regularity in junior high school problems in recent years. The main solution to this kind of problem is to use incomplete induction to solve the problem through experiment, guess, trial and error verification and summary.

Method 4: Direct solution method

Some multiple-choice questions are adapted from some fill-in-the-blank questions, true-false questions and solution questions, so we can often adopt direct methods, directly proceed from the conditions of the questions, draw conclusions directly through correct operation or reasoning, and then compare with the options to determine the options. Most of us will use this method when solving problems.

For example, in the promotion activities of shopping malls, the goods marked 200 yuan will be 20% off on the basis of 20% off, and now the price of the goods is ().

A, 160 yuan b, 128 yuan c, 120 yuan d, 88 yuan.

Method 5: Number-shape combination method

To solve multiple-choice questions related to graphics or images, we often use the thinking method of combining numbers with shapes, and sometimes we have to use other methods comprehensively.

Method 6: substitution method

Substitute the selected branch into the stem of the question or substitute the question into the selected branch for inspection, and then make a judgment.

Method 7: Observation method

Observe the characteristics of trunk and selected branches, and make a choice by distinguishing the differences and connections of each selected branch.

Method 8: Enumeration

List all possible situations and make a correct judgment.

For example, it is enough to change a RMB with a face value of 10 yuan into small change and RMB with a face value of 1 yuan in 2 yuan. The method of change is ().

A.5 species B.6 species C.8 species D. 10 species.

Analysis: If we set the face value of RMB X as 2 yuan and the face value of RMB Y as 1 yuan, it is not difficult to list the equations. This equation has six pairs of non-negative integer solutions, and we choose B.

Method 9: undetermined coefficient method

To find a certain functional relationship, we can first assume the undetermined coefficients, then list the equations (groups) according to the meaning of the question, and then get the undetermined coefficients by solving the equations (groups), thus determining the functional relationship. This method is called undetermined coefficient method.

Method 10: incomplete induction

When a mathematical problem involves many or even infinite situations and it is difficult to start with a chaotic clue, the effective method is to find out the general law and solve the problem by investigating some simple situations.