The GCF of any two odd numbers is always odd. The GCF of any two even numbers is always even. The GCF of an odd and an even number is always odd.
Yes.
No, always odd.
Yes.
Yes.
no, the GCF for 4 and 2 would be 2, which is even
The GCF will, yes.
Yes.
The GCF is, yes.
The GCF is, yes.
Yes.
No not always as for example the GCF of 7 and 21 is 7