You need at least two numbers to find a GCF.
The greatest common factor of 18 and 21 is 3.
The GCF is 3.
The GCF is 3.
The greatest factor of 21 and 16 is 21, which is a factor of 21 but not of 16.
The greatest common factor of 21 and 77 is 7.
The common factor of 3 and 21 is 3. *
7 is the greatest common factor of 14 and 21.
The common factors of 21 and 42 are 3, 7 and 21. The greatest common factor (GCF) is 21.
The Greatest Common Factor of 21, 63, 84: 21
The greatest common factor of 21 and 75 is 3.
The greatest common factor of 21 and 162 is 3.
The greatest common factor of 21 and 322 is 7.