The GCF is 1.
This is a ridiculous question, due to the fact that 31 is a prime number. Therefore, as 31 is not a factor of 30, the highest common factor can only be 1.
The GCF is 1 since there are no common factors.
The GCF is 31.
The GCF is 1.
The GCF is 31.
The GCF is 1.
The GCF is 1.
The GCF is 1.
The GCF of 31 and 6 is 1.
The GCF is 30.
The GCF is 31.
1 is the GCF of 33 and 31 because 31 is a prime number.