Any prime number with its multiple.
Any two composite numbers who do not share the same prime factors.15 = 5x322 = 11x2So 15 and 22 have a GCF of 1
52 is composite. You need at least two numbers to find a GCF.
Any consecutive composite integers, like 34 and 35.
6 and 8
If the GCF of two composite numbers is 1, they are co-prime or relatively prime.
All numbers (except 0 and 1) are either prime or composite. All composite numbers can be expressed as the product of prime factors. So the GCF will either be a single prime number or a combination of prime numbers. Of course, if there are no common prime numbers, the GCF is 1.
When 2 numbers have their GCF = 1, it means that the numbers are relatively prime to each other, which doesn't necessarily mean that they are prime on their own. There are 2 cases where relative prime can be guarenteed: All prime numbers are guarenteed to be relatively prime to all other prime numbers. Any prime number is guarenteed to be relatively prime to any composite number smaller than the prime number. If neither of the above 2 conditions are met, manual calculations must be done to find any existing GCF.
Any two coprime numbers
Any consecutive even numbers.
The GCF is 1.
The GCF of all the composite numbers under 100 is 1. For e.g 4 & 9 are composite numbers & their GCF is 1, so if we take other composite numbers along with 4 & 9 the GCF will be 1.