15,9,6
Break them all down as far as they will go:
15 = 3*5
9 = 3*3
6 = 2*3
We look at the factor 2. 15 contains it no times. 9 contains it no times.
6 contains it 1 time. The most number of times that any of the three
contains factor 2 is 1 time. So the LCM will contain it 1 time. So write
LCM = 2×____
We look at the factor 3. 15 contains it 1 time. 9 contains it 2 times.
6 contains it 1 time. The most number of times that any of the three
contains factor 2 is 2 times. So the LCM will contain it 2 times. So write
LCM = 2×3×3____
We look at the factor 5. 15 contains it 1 time. 9 contains it no times.
6 contains it no times. The most number of times that any of the three
contains factor 2 is 1 time. So the LCM will contain it 1 time. So write
LCM = 2×3×3×5
And that's all the factors, so we multiply them all together, and get
LCD = 90
Edwin
