The GCF is: 3
The GCF is 21.
The GCF is 7.
The GCF is 21.
The GCF is 21.
The GCF is 21.
The GCF is 21.
The GCF is 21.
The GCF is 21.
The GCF is 7.
The GCF of 21 and 42 is 21. The GCF of 17 and 27 is 1.
It is: 21
42:1,2,3,6,7,14,21,4263:1,3,7,9,21,6398:1,2,7,14,44,98The GCF is seven.