The problem of planting trees is an applied problem to study the relationship between the total length, interval distance and the number of trees in the planting area. The application of tree planting is basically divided into two categories: planting trees along the road; Plant trees along the perimeter.

Planting trees along the road, because one tree should be planted at both ends, so the number of trees planted is more than the number of divided sections1; Planting trees along the perimeter, because the head and tail overlap together, the number of trees planted is equal to the number of segments.

The basic method to solve the problem of planting trees is:

(1) Plant trees along the road

Number of trees = total length/interval+1

Interval = total length ÷ (number of trees-1)

Total length = interval × (number of trees-1)

(2) Planting trees along the periphery

Number of trees = total length ÷ interval

Interval = total length and number of trees

Total length = interval × number of trees