The greatest common factor (GCF) refers to a factor that is COMMON to two or more numbers. You have only one number in the question! The greatest factor of any number is itself.
Furthermore, the word "GREATEST" is a superlative adjective and that means there can be only one.
The GCF is 28.
The GCF is 4.
The GCF is 1.
The GCF is 14.
The GCF is 4.
The GCF is 2.
The GCF is 28.
The GCF is 2.
The GCF is 14.
The GCF is 14.
The GCF is 28.
The GCF is 4.