They are relatively prime, like 4 and 9.
They are called prime numbers.
are co-prime
All numbers have a common factor of 1. Sometimes that's the only common factor.
The only common factor of these numbers is 1.
The factors of three are both odd numbers.
It has none - you can only have a common factor between two or more numbers.
Yes. Not counting one as a factor, you could have numbers like 6 and 10 which only share one common factor, 2.
The only factor they have in common is 1.
Their only common factor is 1.
The least common factor of any set of numbers is 1.
6 is a factor of 36 but a common factor is only applicable to two or more numbers.
Yes, a pair of numbers can have fewer than two common factors. This only happens when the numbers are co-prime -- that is, when the numbers have only one common factor. In that case, the common factor is always 1.