i have not done LCD for 7 years. im still reading about it and i still dont get it. can some one help me?

Question

anonymous · Answer

The LCD of two numbers is the smallest number that both multiply into by some other number.

anonymous · Answer

ok. so what would the lcd of 20 be? for example

anonymous · Answer

Find an example in a book. It usually involves two numbers

anonymous · Answer

LCD is between two or more numbers.

anonymous · Answer

LCD of 5 and 3 is 15, because that is the smalled number both 5 and 3 go into.

anonymous · Answer

ok. i get it now. thanks so much:)

anonymous · Answer

here is how you find it for big numbers: factor each number into prime factors, then take each prime to the highest power you see in any one number.  5 and 3 are both primes, so just multiply.  
but for say 8 and 12 you would write $$8=2^3$$ $$12=2^2\times 3$$ so least common multiple is $$2^3\times 3 = 24$$ of course you might have just seen the 24, but for 84 and 98 you would probably not see the answer.
$$84=2^2\times 3 \times 7$$
$$98=2 \times 7^2$$
least common multiple  is 
$$2^2 \times 3 \times 7^2 = 588$$