The GCF is 1.
The GCF is 1.
16 and 21
The GCF is 3.
16: 1 2 4 8 16 21: 1 3 7 21 gcf: 1
The GCF is 4.
The GCF is 4.
The GCF of 12, 16 is 4.
The GCF of 16 and 30 is 2.
GCF of 21 and 42: 21GCF of 16 and 25: 1
The GCF is 3.
The GCF is 1.
If you want the "greatest", then there can only be one of it.You can't have two different numbers and say that they'reboth the "greatest".The greatest common factor of 12 and 21 is 3 .