In one sense, the opposite of the GCF could be the least common factor, but the least common factor of any set of positive integers is 1, so it's not very interesting.
No. Common factors are common factors. The largest of these is known as the GCF, but it's still a common factor.
The GCF is 6.
The GCF is 9.
The GCF is 4.
The GCF is 30.
50
The GCF is: 1
The GCF is 27.
The GCF is 1.
The GCF is 2.
The GCF is 3.