When you are reducing fractions.
The common factor of 4 and 9 is 1.
It won't help. The lowest common factor of any two positive integers is 1.
The greatest common factor is used to reduce fractions.
It's not useful. The least common factor is always 1.
The greatest common factor of 6 and 9 is 3.
Use the GCF. The LCF is always 1.
divisor
You don't. The lowest common factor is always 1.
Never. The least common factor of any set of positive integers is 1.
Use the following factor trees to determine the answer355, 7and637, 97, 3, 37 is the common factor of 35 and 63
To reduce fractions
When simplifying fractions.