5.2. Write the numbers $1,2,3,4,5,6,8,9$ (that is, all numbers from 1 to 9 except 7) in a row so that in any pair of adjacent numbers, one divides the other.
Answer. For example, $9,3,6,2,4,8,1,5$.

Remark. There are other examples. However, in each correct example, the number 5 is at the edge, and next to it is the number 1.

Comment. Any correct example - 7 points.