**Abbreviated "GFC", it's looking at two numbers and finding the largest of their factors.** I mostly made this note so that I didn't forget that 'GFC(36, 99)' means "the greatest common factor of `36` and `99`". It's 3, by the way. - 36: factors are `[1, 3, 6, 12]` - 99: factors are `[1, 3, 9, 11, 33]` Note this is using factorization, **not prime factorization**. So the greatest common factor doesn’t NEED to be a prime. The GCF of `8` and `12` is `4`. **** # More ## Source ## Related - [[Relatively Prime]]