What is the LCM of 210 and 450?

Answer 1

Start by factoring both numbers into primes:

210 = 2*3*5*7

450= 2*3*3*5*5

What's the shortest list that includes all the factors of both numbers?

One 2, two 3's, two 5's, one 7

That's the recipe for lcm in this problem.

lcm = 2*3*3*5*5*7

= 3150