There cannot be a greatest common factor (GCF) of just one number. To be common there need to be at least two numbers. If you find all the factors of two or more numbers, and you find some factors are the same ("common"), then the largest of those common factors is the Greatest Common Factor.
4
The GCF is 8.
2
It is 34
The GCF is 3.
The GCF is 12.
It is two.
The greatest common factor of 8 and 32 is 8.
The greatest common factor of 8 and 24 is 8.
The greatest common factor of 8 and 400 is 8.
The greatest common factor of 1624 , 8 = 8
The GCF of 8 and 96 is 8.The Greatest Common Factor is 8