Math
posted by Ann .
Find the least common multiple (LCM) for each of the following groups of numbers
12, 20, and 35

That would be the number that contains the prime factors of all of the three numbers, for the maximum number of times that they appear in any single number.
12 = 3*2*2
20 = 2*2*5
35 = 5*7
The LCM is 2*2*3*5*7= 420