What is the least common multiple of 3 8 12and15?

Answer 1

First, toss the 3. Since it is a factor of 12, it will have no effect on the answer.

Take the LCM of the larger pair, then take the LCM of that answer with the smallest number.

LCM is the product divided by the GCF
12 factors to [2 2 3]
15 factors to [3 5]
common factor is [3] so GCF=3
LCM = 12 * 15 / 3 = 60

60 factors to [2 2 3 5]
8 factors to [2 2 2]
common factors [2 2] so GCF=4
LCM = 60 * 8 / 4 = 120 ■
(120 / 3 = 40) (120 / 8 = 15) (120 / 12 = 10) ( 120 / 15 = 8) All checks.