(1) In terms of time, if we start at the same time, it will take the same time to catch up with each other; ② Considering the distance, a. On a straight line, the difference between two people's distances is equal to the distance they need to catch up with, b. In a circular movement, the difference between two people's distances is equal to the length of a week (starting from the same point); Considering speed, the relative speed of two people is equal to the difference between their speeds.

To solve the problems encountered, we usually draw a "line diagram" to analyze the problems. In general, the problem of meeting can be found from the following aspects, and the equation can be made: ① Considering the time, two people start at the same time, and the time spent when meeting is equal; (2) Considering the distance, a. Moving in a straight line, two people walk in opposite directions, and the sum of the distances they walk when they meet is equal to the whole distance. B. In circular motion, two people walk back to each other from the same place, and the sum of the distances they walk when they meet each other is one week; (3) Considering speed, two people walk in opposite directions, and their relative speed is equal to the sum of their speeds. The encounter problem is very intuitive, and it is a good method to analyze the equidistant relationship equation by drawing "line segment diagram"