LCM Problem?

Question

What is the Least Common Multiple of

9:
16:
25:

Answer 1

To find the LCM you should first factor your numbers into their Prime factors:

9 = 3*3
16 = 2*2*2*2
25 = 5*5

The next thing you do take the factors from the number with the most of that factor... in this case they are all different so you use them all...in this case you have 2*2*2*2*3*3*5*5.. and figure out what that number is...3600

if you had numbers like:
8 = 2*2*2 <-- use all three 2's
18 = 2*3*3 <-- only has One two (which is already covered from the number above) so ignore it, use the two 3's
24 = 2*2*2*3 <-- ignore because you have already have three 2's and two 3's from the numbers above:
2*2*2*3*3 = 8*9 = 72
now check: 72/8 = 9, 72/18 = 4, 72/24 = 3 and there are NO common factors between 3,4, and 9 (none in all 3 of the numbers)... so our LCM is 72 for 8, 18, 24

Answer 2

3600...