In practice, we determine all the divisors of a number using their prime factors. Let's determine, for example, the dividers of 90:

1) we break down the number into prime factors;

2) draw a line and write 1 at the top, because it is divisor of any number;

3) we multiply successively each prime factor by the dividers already obtained and write these products next to each prime factor;

4th) the dividers already obtained need not be repeated.

Therefore the **90 dividers** are **1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90**.