You don't; you need at least two numbers to find a GCF.
You need at least two numbers to find a GCF.
The GCF is 26.
The GCF is 26.
The GCF is 6.
The GCF is 3.
The GCF is 2.
The GCF is 2.
The GCF of 78 and 30 is 6.
The GCF is 1.
The GCF is 3.
The GCF is 2.
gcf(100, 78) = 2