Question

Greatest common factor 12,30,72

Answer 1

The first step is to write the prime factors of each number. We have

12 = 2 x 2 x 3

30 = 2 x 3 x 5

72 = 2 x 2 x 2 x 3 x 3

Looking at the factors, one 2 and one 3 are common to all three list of factors. Thus,

Greatest common factor = 2 x 3 = 6