20 and 7 have no common factors other than 1.
5 (leaves you with 2, 4 and 7)
HCF is the highest common factor of two or more numbers. HCF of 20 and 200 is 20.
The HCF is 7.
The GCF is 20.
The GCF is 7.
The GCF is 7.
The GCF is 4.
The GCF is 7.
The GCF is 1.
The GCF is 7.
20