Question

what is the the l.c.m of 60 and 15

Answer 1

60

Answer 2

It's 3

Answer 3

isn't that the least common denominator?

Answer 4

It's the least common multiple. To find the LCM, you write out all the factors of each number and pick the factor they have in common that is lowest.

Answer 5

I thought the lcm had to actually be a multiple of both of the numbers

Answer 6

It does. 3 is a multiple of 60 *and* 15, since

3x20 = 60
3x5=15

Answer 7

How i understand it is that the lcm would be the smallest number that both numbers are equal to when multiplied by an integer, such as
15x=0 ,15x1=1, 15x2=30, 15x3=45, 15x4=60
60x0=0, 60x1=60
so they both share 60?

Answer 8

In general:

To find the lowest common multiple (LCM) of two or more numbers, list the multiples of the larger number and stop when you find a multiple of the other number. This is the LCM.

Answer 9

Ok thanks I think I get you now.

Answer 10

Here, check this link out:

http://www.mathsteacher.com.au/year7/ch03_prime/03_lcm/lcm.htm

It goes through some examples. You'll see what I mean.

Answer 11

According to the link you gave me, the lcm of 6 and 9 is 18...why not 3 like it is for 15 and 60?

Answer 12

Yeah, I'm absolutely sorry - I've been thinking of the wrong thing the whole time. This is what happens when I multitask - I begin to stuff simple things.

The LCM of 60 and 15 is 60. You were right.

Answer 13

My apologies.

Answer 14

Yeah I can see that you are answering all of the harder questions that are posted, I just got confused when you said it was three though, but its alright.

Answer 15

Stupid definitions ><