To work this out, you need to write both numbers as their prime factors:
20 = 2x2x5
12 = 2x2x3
The next step is to identify any common prime factors. In this case both numbers have two 2s as prime factors. Multiply these together and you get 4. Therefore 4 is the HCF of 20 and 12.
the hcf of 12 and 20 = 4
4
4
The GCF is 2.
The GCF is 4.
The GCF of 12 and 20 is 4.
The GCF is 2.
20/12 = 5/3 by dividing the numerator and denominator by their HCF which is 4
The HCF of 12 and 60 is 12
The GCF is 12.
The GCF is 2.
HCF is the highest common factor of two or more numbers. HCF of 20 and 200 is 20.