When the numbers are relatively prime.
The product of the GCF and LCM is equal to the product of the original two numbers.
The general rule is that the product of the LCM and the GCF is equal to the product of the original two numbers. That would make the answer 20. Lets overlook the fact that two numbers with a GCF of 15 and an LCM of 20 don't exist.
The LCM of two numbers is one of the numbers when one of the numbers is a multiple of the other. The LCM of two numbers is the product of the numbers when they are relatively prime. In all other cases (like consecutive even numbers that aren't 2 and 4) the LCM is as you describe.
Two or more numbers are needed to find their LCM
In number theory, the product of two positive integers will equal the product of their GCF and LCM. Dividing that product by one of them will give you the other.
It is multiplication
The product of the GCF and LCM is equal to the product of the original two numbers.
only if they are equal
Since the product of two numbers is equal to the product of their GCF and LCM, the GCF of two numbers is equal to their product divided by their LCM and their LCM is equal to their product divided by their GCF.
The product of the GCF and LCM of a pair of numbers is equal to the product of the numbers.
The GCF of two numbers multiplied by their LCM will equal the product of the original numbers. If you know the GCF, divide it into the product of the two. The result will be the LCM. If the GCF of two numbers is 1, the LCM is their product.
The product of the GCF and LCM of a pair of numbers is equal to the product of the numbers.
The product of the GCF and the LCM of two numbers is equal to the product of the original two numbers. Multiply the GCF and the LCM. The original two numbers will be another factor pair of that total. Find the factor pair that has that GCF and LCM.
When the two numbers are relatively prime.
Hardly ever.
The LCM of two numbers multiplied by their GCF will equal the product of the original numbers. If you know the LCM, divide it into the product. The result will be the GCF.
The product of the GCF and LCM of two numbers will equal the product of the two numbers.