(1) Plant trees at both ends.

The number of trees is more than the number of segments 1.

Number of linear trees = number of line segments+1= distance-tree spacing+1, distance = tree spacing × (number of trees-1), and tree spacing = total length-1)

② Planting trees at one end

The number of trees equals the number of segments.

Number of trees = total length-tree spacing, total length = tree spacing × number of trees, tree spacing = total length-tree spacing.

③ No trees are planted at both ends.

The number of trees is less than the number of segments 1.

Number of trees = number of segments-1= total length-1, total length = tree spacing × (number of trees+1), tree spacing = total length-1)

The application problem of primary school mathematics is the foundation of junior high school mathematics, and planting trees is one of the most representative problems in the application problem. The problem of planting trees is to plant trees at equal intervals. Of the three quantities of distance, the distance between trees and the number of trees, two are known and the third quantity is found. In order to be more intuitive, it is illustrated by graphic method. Trees are represented by points, and the lines along which trees follow are represented by lines, thus transforming the problem of planting trees into the problem of the relationship between "points" on an unclosed or closed line and the number of line segments between two adjacent points.

Example:

How many trees does it take to plant a tree every 5 meters on a 20-meter-long road?

Solution:

Interval number = total length ÷ interval length: 20÷5=4 (pieces)

Number of trees = interval number+1: 4+ 1 = 5 (trees)

A * * * needs five trees.