Numbers 
Factors 
Common Factors 
GCF 
15 
±1, ±3, ±5, ±15 
±1, ±5 
5 
25 
±1, ±5, ±25 
Numbers 
Factors 
Common Factors 
GCF 
36 
±1, ±2, ±3, ±4, ±6, ±9, ±12, ±18,
±36 
±1, ±2, ±3, ±4, ±6, ±12 
12 
24 
±1, ±2, ±3, ±4, ±6, ±8, ±12,
±24 
Numbers 
Factors 
Common Factors 
GCF 
30 
±1, ±2, ±3, ±5, ±6, ±10, ±15, ±30 
±1, ±2, ±5, ±10 
10 
20 
±1, ±2, ±4, ±5, ±10,
±20 
50 
±1, ±2, ±5, ±10, ±25 
Example of Relatively Prime
Numbers
Numbers 
Factors 
Common Factor 
GCF 
32 
±1, ±2, ±4, ±8, 16, ±32 
±1 
1 
65 
±1, ±5, ±13,
±65 
Note that in this example neither 32 nor 65 are
prime. Since they have the number 1 as the only common factor, 32 and 65 are
relatively prime to each other.
