what is the lcm of 12,11,7,5,39,10? ( please answer this! an expert needs to answer it)?

Question

SORRY! READTHIS! I MEANT 12, 11,7,5,3,9,10. IT'S NOT 39. IT'S 3,9 , TWO DIFFERENT NUMBERS. TELL ME THE ANSWER DON'T TELL HOW TO FIGURE IT OUT. PLEASE! I LOVE U . HELP ME!

Answer 1

You SHOULD be able to do this for yourself. Don't feel blown away simply because the result is large!

With your corrected list: 12,11,7,5,3,9,10, the lcm will be:

12 x 11 x 7 x 5 x (1)* x (3)** x (1)***.

The REASONS?:

* This is 1, not 3, because 12 already contains a 3.
** This is 3, not 9, because 12 already contains a 3; so, to get a 9 in the final product, you only need one more 3.
*** This is 1 because a 2 already exists in the 12, and the 5 needed to give you 10 in the end result has already appeared, as (plain) 5 itself.

So, to recap, the lcm is 12 x 11 x 7 x 5 x (1)* x (3)** x (1)*** i.e. 12 x 11 x 7 x 5 x 3 = 13860.

In future, use similar methods, don't just ask others to do it for you.

Live long and prosper.

Answer 2

If they were all coprime, you'd just multiply them all together to get 12*11*7*5*39*10, ie 1801800.
However, we have one repeated factor of 2 (from the 12 and 10), and one repeated factor of 3 (from 12 and 39) while all of the other primes only occur once. So divide by 2*3: 300300.

For your changed question:
Now that there are quite a few common factors, its easiest to split everything into prime factors:
2*2*3, 11, 7, 5, 3, 3*3, 2*5.
Now, for each prime, find the number which uses it the most times, and put that in the answer:
2 occurs twice at most (in the first number), 3 occurs twice, etc.
So we get 2*2 * 3*3 * 5 * 7 * 11 = 13860.