What is LCM of 24 and 18 using prime factorization?

Answer 1

In order to find least common multiples (LCMs) using prime factorization, start by factoring each number all the way down to prime numbers (numbers that are only divisible by one and themselves).

18 = 2*3*3 (or 2 * 3^2)

24 = 2*2*2*3 (or 2^3 * 3)

Pull all of the factors from one of the numbers (I'll use 2^3 * 3), and then, since we want the least common multiple, we'll need to include factors from the other number that weren't already used.

Since I already have 2^3, I don't need to multiply by 2, but since 18 has 3^2, and I'm only using 3, I need to multiply in another 3.

So, 24*3 = 72, which is the LCM of 24 & 18.

Answer 2

2 x 3 x 3 = 18

2 x 2 x 2 x 3 = 24

2 x 2 x 2 x 3 x 3 = 72, the LCM

Answer 3

24 = 2^3*318 = 2*3^2

So LCM = 2^3*3^2 = 72