How do you figure least common multiple of 4 5 12?

Answer 1

Long way is write multiples of each number until you get a match.

4 8 12 16 20 24 28 32 36 40 44 48 52 56 60

5 10 15 20 25 30 35 40 45 50 55 60

12 24 36 48 60

another way (especially useful with larger numbers)

lay down prime factors of each number

4 = 2 * 2 = 2^2

5 = 5 = 5^1

12 = 2 * 2 * 3 = 2^2, 3^1

take highest power of each factor = 2^2, 3^1, 5^1 = 2 * 2 * 3 * 5 = 60