When you are trying to add or subtract unlike fractions.
Wiki User
∙ 2015-12-14 04:18:21Wiki User
∙ 2011-02-25 16:23:01Most often in comparing, adding and subtracting fractions.
Gcf you use when you are finding the greatest factor for the numbers. Lcm you use when you are finding the smallest multiple in the numbers factors
Use the GCF to reduce equivalent fractions. Use the LCM to add and subtract unlike fractions.
a and b have no common prime factors. Their LCM is their product.
You need at least two numbers to find an LCM no matter what you use.
The GCF is 7.The LCM is 70.
you use the lcm (least common multiple).
Gcf you use when you are finding the greatest factor for the numbers. Lcm you use when you are finding the smallest multiple in the numbers factors
The LCM of 8 and 108 is 216, no matter what you use.
You can, but there are more efficient ways to find the LCM.
LCM of 96 and 45 is 1440.
We use the LCM to find the least common denominator of unlike fractions.
Use the GCF to reduce equivalent fractions. Use the LCM to add and subtract unlike fractions.
To find the GCF and the LCM you have to first at least try to use prime factorization. So use factor trees. Or for the LCM find th least common multiples of the number.
You would use it when adding fractions.
a and b have no common prime factors. Their LCM is their product.
The HCF helps when reducing fractions. The LCM helps when adding or subtracting fractions.
It doesn't matter which method you use. You still need at least two numbers to find an LCM. There is no LCM of 20.