You need at least two numbers to find a GCF.
The GCF is 21.
The GCF is 5.
The GCF is 5.
The GCF is 5.
The GCF is 5.
The GCF is 5.
The GCF is 5.
The greatest common factor (usually abbreviated GCF) of 15, 35, and 20, is 5.
The GCF is 5.
The GCF is 5.
The GCF is 5.
The GCF is 5.