The lowest common factor is 1.
Did you mean the greatest common factor (GCF) or maybe the least common multiple (LCM)?
The GCF is the biggest number you can factor out of a list of numbers.
If you have 4, 12, and 14, the GCF is 2 because 2 is the largest number that goes into 4, 12, and 14.
The LCM is the smallest number into which a list of numbers can factor.
If you have 4, 12, and 14, the LCM is 84 because 84 is the smallest number that 4, 12, and 14 can all go into.