The core idea of step-by-step problem solving method is to gradually narrow the solution space of the problem and find the solution that meets the meaning of the problem by constantly eliminating the unusable options. In the process of solving problems, it is necessary to determine the maximum range of problems, and then check them one by one from the maximum value to gradually narrow the solution space. Some restrictions can be determined by some special properties or laws, and options that do not meet the meaning of the question can be further excluded.

1, people walk in the direction of the escalator.

This situation is equivalent to "drifting with the flow" in running a boat. The water speed here is the running speed of the escalator itself. At this time, the escalator is to help people walk, and * * * has passed the total number of escalators. Compared with the problem of running a boat before, we can get:

The actual speed of people on the escalator = people's speed+escalator speed.

Total steps of escalator (i.e. the length of escalator) = actual speed of people on escalator × time = (speed of people+speed of escalator )× time = time × speed of people+time × speed of escalator = steps of people walking+steps of escalator running automatically.

When people go backwards along the escalator.

This situation is equivalent to running a boat "upstream". At this time, the speed of people is greater than the speed of the escalator before they can walk to the other end of the escalator. In this case, the number of steps people walk is greater than the total number of escalators, and escalators do not help, offsetting the number of steps some people walk, then we can get:

Actual speed of people on escalator = speed of people-speed of escalator.

Total escalator steps (that is, escalator length) = actual speed of people on the escalator × time = (human speed-escalator speed )× time = time × human speed-time × escalator speed = steps taken by people-steps automatically operated by the escalator.

How to learn mathematics well;

1, master basic knowledge, which is the basis of learning mathematics well.

Although mathematics is difficult for many students, for students who want to learn mathematics well, the first thing to do is to master the basic knowledge, which is the basis of learning mathematics well.

The basic knowledge of mathematics is generally the knowledge of some concepts and formulas. Only by mastering these clearly can students have a good application and mathematics be improved.

2, think more, thinking is the key to flexible use of knowledge.

Mathematics is a subject that attaches great importance to the logical thinking ability, so students should use knowledge flexibly in the process of learning, which is the key factor to learn mathematics well. Students' thinking is exercised in the process of continuous thinking. Only by thinking deeply often can their thinking be more active and their mathematics learning be easier.

3. Listen carefully in class. Classroom is an important link to master and expand mathematics knowledge.

In class, the teacher usually talks about the idea of doing the problem and some expanded knowledge. If students can keep up with the teacher's thinking in class, then on the whole, such students have good math scores, so if they want to do well in math, they should listen carefully in class.