Help me as many as you can.

DS, I highly suggest you look at this website:
http://www.mathmix.com/content/Subjects/Numbers/Factoring_Numbers/Least_Common_Multiple 

Here's an example:

Thank you! Now I don't have to do the old way!

First, find all prime factors. Then, find the highest exponent of each number and multiply all the numbers with the highest exponent. Basically, you will have 1 of each number.

What is the 5^0 supposed to mean?

What are the prime factors for 5 and the odd numbers?

The 5^0 acts as a 1 as well as a way to differentiate the highest exponents for each number. If you have put all the possible different numbers, then it'll be easier to see which ones have the highest exponent.

For 5, it would just be 1 X 5 --> 1^1 * 5^1...

Note, for 3,5,7

you would also have to add 3^0 and 7^0 to the list of 1^1 * 5^1 * ..... * .....

Note that you will see the LCM of all prime numbers is basically the multiplication of all the prime numbers. So, it'll be 3*5*7!

Like this?

1^1 * 5^1 * 1^1 * 3^1 * 1^1 * 7^1?

So the answer is 105!

Yep, well you only need one 1^1 since you want only 1 of each number but it doesn't matter much since it's just 1.

Ok for the last one, the folowing is the answer

2*3*5*7=210!

Check your answers with http://www.mathsisfun.com/least-common-multiple-tool.html.

What can make 12?

12 --> 2*2*3 --> 2^2 * 3^1.

Help

4, 9, 12