The factor of what.
The GCF is 1.
You are 12-20. The only common factor of 11 and 21 is 1.
The greatest common factor of 20, 21, and 25 is 1. Although 20 and 25 can be divisible by 5, 21 can not. Therefore, the only common factor between these three numbers is 1 and it's the greatest one as well.
Greatest common factor of 20 & 51 is 1. Factors of 20 are 1, 2, 4, 5, 10 & 20. Factors of 51 are 1, 3, 17 & 51. The only common factor is 1, so GCF is 1. Alternate method: Prime factorization of 20 = 2x2x5 Prime factorization of 51 = 3x17 From the prime factorizations it is clear that 1 is the GCF of 20 and 51.
1) There isn't such a thing as a least common factor. If you really wanted to know, it is always 1. 2) You can't have something in common between only one thing. greatest common factor and least common multiple require you to compare two numbers.
The only common factor is 1.
The GCF is 1.
16
1 and 4
The least common factor is: 1
You are 12-20. The only common factor of 11 and 21 is 1.
The GCF is 1.
12, 16 and 18
There are no factors of 50 in that range.
1, 2, 4, 5, 10, 20, 25
12, 16 or 18
The factors of 50 are: 1, 2, 5, 10, 25, 50 None of them is between 11 and 20.