how do u use GCF and LCM?

Answer 1

In mathematics, the greatest common divisor (gcd), sometimes known as the greatest common factor (gcf) or highest common factor (hcf), of two non-zero integers, is the largest positive integer that divides both numbers.

The greatest common factor is useful for reducing vulgar fractions to be in lowest terms.

n arithmetic and number theory the least common multiple or lowest common multiple (lcm) or smallest common multiple of two integers a and b is the smallest positive integer that is a multiple of both a and b. If there is no such positive integer, e.g., if a = 0 or b = 0, then lcm(a, b) is defined to be zero.

When adding or subtracting vulgar fractions, it is useful to find the least common multiple of the denominators, often called the lowest common denominator.

Answer 2

For LCM you break the numgers down say 4 and 6. 4=2 times2 and 6= 2 times 3 and 2times 2 = 2 squared on one side and you take the highest of every number on each side so your LCM=2 squared times 3 which is 12 and six and 4 both go into 12 in GCF you take the lowest number that there is 2 of so GCF=2 and 2 goes into 4 and 6.

Answer 3

They're both used to reduce fractions down to lowest terms. And the difference between GCF (Greatest Common Factor) and LCM (Least Common Multiple) is the approach by which they try to reduce the fraction.

GCF attempts to find the LARGEST number that can be divided into both numerator and denominator. Dividing both by this number ultimately reduces it down as far as it can go.

LCM attempts to find the smallest denominator by looking at the factors of the numberator and denominator.

FYI, in my class, I don't even the my students the LCM because I think it's too complicated for them. Personally, I find the GCF method easier.

But regardless of which one you use, GCF or LCM, you will still get the same answer.