It is: 3
The GCF is 3.
It is: 5
The GCF is 1.
The GCF is 3.
The GCF is 3.
The GCF is 1.
The GCF is 1.
The GCF is 5.
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 .
The GCF is 3.
The GCF is 3.
The GCF of 12, 21, and 88 is 1.