# factorization ?

• Apr 25th 2006, 11:04 PM
Sandra14
factorization ?
Can someone please show me how to find the lcm useing prime factorization ? i am so confused about this here is a sample problem 18 and 24
• Apr 26th 2006, 06:10 AM
earboth
Quote:

Originally Posted by Sandra14
Can someone please show me how to find the lcm useing prime factorization ? i am so confused about this here is a sample problem 18 and 24

Hello,

1. Transform both numbers into a product of prime factors:
18 = 2 * 3 * 3
24 = 2 * 2 * 2 * 3

2. The lcm consists of all prime factors so that each number is completely in the lcm:

$lcm = \underbrace{2 * 3 * 3}_{\csub{thats\ for\ 18}}* \underbrace{2*2}_{\csub{addition\ to\ get\ 24}}=72$

Greetings

EB
• Apr 26th 2006, 11:08 AM
earboth
Quote:

Originally Posted by Sandra14
Can someone please show me how to find the lcm useing prime factorization ? i am so confused about this here is a sample problem 18 and 24

Hello,

it's me again.

I've attached a diagram to show you how you can find the lcm for 2 and more numbers by using prime factorization.

Maybe you need some time to understand the "mechanic" which is used. But if you've understand it, it's a very easy way to do a very unpleasent calculation.

Good luck.

EB
• Apr 26th 2006, 02:21 PM
ThePerfectHacker
Quote:

Originally Posted by Sandra14
Can someone please show me how to find the lcm useing prime factorization ? i am so confused about this here is a sample problem 18 and 24

The easiest method I know if it done through the Euclidean Algorithm. You basically work with the greatest common divisor. There is a theorem that:
$\gcd(a,b)\cdot \mbox{lcm} (a,b)=ab$
If you understand what I said, good. If you like me to explain how to use this to find both the greatest common divisor and lowest common multiple please ask.