Question

Find the LCM of these numbers.

10, 12, 15 Type the correct answer.

Answer 1

60 is the first multiple they have in common. 10 and 15 have 30 in common, but 12 doesn't, so you have to find the next one.

Answer 2

another way to do this is to write them as prime factors

10 = 2*5
12 = 2*2*3
15 = 3*5

where there are duplicates you just use one of the numbers so
LCM = 2*2*3*5 = 60