There are several possibilities of pairs of numbers whose greatest common factor is 18.
54 and 198
18 and 126
414 and 846
72 and 1422
14 and 28 are two even numbers between 10 and 30 whose greatest common factor is 14.
7 and 14
The numbers are 5 and 10.
Relatively prime or co-prime.
120 and 144
That happens when one of the numbers is a factor of the other.
14 and 28 are two even numbers between 10 and 30 whose greatest common factor is 14.
29 and 4147
this is hard
16, 32 and 48
The GCF is 16.
12 and 20
16 and 8
In that case, one of the numbers is a multiple of the other.
27 = 3*936 = 4*945 = 5*927, 36, and 45 are three different numbers whose greatest common factor is 9.
30 and 60, among others.
7 and 14