1. Divisors of the number 660: $1,2,3,4,5,6,10,11,12,15,20,22$, $30,33,44,55,60,66,110, \ldots$.

Divisors of the number 72: $1,2,3,4,6,8,9,12,18,24,36,72$.

The desired pairs of numbers: 6 and 2, 10 and 6, 12 and 8, 22 and 18.
1. Write the set of all distinct divisors of the number 660. Write the set of all divisors of the number 72. Form the set of pairs of numbers that satisfy the following conditions: one number is taken from the first set and one number from the second set, and such that the difference between the first and the second numbers is four.