Yes. Any two primes will have 1 as their Greatest Common Factor. 3 and 5, for instance.
The GCF of any two odd numbers is also odd.
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, it has to be odd.
The GCF of any two odd numbers is always odd because odd numbers don't have any even factors. The GCF of any two even numbers is always even because even numbers are divisible by two and any common factors would have at least one two in common. The GCF of an even and an odd number is odd because odd numbers don't have any even factors.
The GCF of consecutive odd numbers is 1.
no, the GCF for 4 and 2 would be 2, which is even
The GCF will, yes.
The GCF is, yes.
Yes.
Yes.
Yes.
No, their GCF is always odd.