How do you find least common multiplier(LCM)?

Question

I can't seem to figure this out. I need to get the right way of doing it. Can anyone make this make sense in simple terms. PLEASE!

Answer 1

write both numbers as a product of all prime numbers. For example: 18 = 2^1 * 3^2 and 14 = 7^1 * 2^1

take the ones not in common (3^2 * 7^1 = 63) and the ones in common (2^1) and multiply .. Answer = 126

Answer 2

look LCM refers to least common multiple..
eg:if u wana find LCM of 4\7+5\14
=4*2\7*2+5*1\14*1
=8\14+5\14
hence the answer(the only thing u have to do is make the denominator common and u can solve the sum)
hope answer the question
thnx

Answer 3

lcm is same as least common denominator when adding fractions

you can list the multiples of each term and then find the smallest common one

eg adding 1/3 and 1/4


multiples of 3 are 3,6,9,12
multiples of 4 are 4,8,12

12 becomes the LCM

you can also use factor trees, but this is to hard to explain here

Answer 4

if you have 2 numbers for example 5 and 2 then the LCM would be 10. the easiest way to work this out is to times the 2 numbers together but if you have 3 numbers 2,6,10 then the LCM would be 30 as 10x3=30 6x5=30 and 2x15=30

Answer 5

Find all the prime factors of the numbers. then find out the largest number of times they have to be multiplied to get any one of the number, i.e their highest power. then multiply all the prime factors with their highest powers.

for example if you want to find out the LCM of 16, 24, 36, then

16=2*2*2*2=2^4

24=2*2*2*3=2^3*3

36=2*2*3*3=2^2*3^2

therefore the prime factors are 2 and 3, and the highest powers of them are 4 and 2 respectively.

therefore, LCM= 2^4*3^2=144

Answer 6

Any number can be written as the result of the product of prime numbers. A prime number is a number that cannot be divided by any smaller number (1 does not count as a number for this exercise).

For a given number, this product is unique.

For example, the number 420 is the result of this product:
2*2*3*5*7.

If you are given a list of numbers and asked to find the LCM, you begin by finding the list of prime factors of each number.

Example: 420, 632, 9

420 = 2*2*3*5*7
632 = 2*2*2*79
9 = 3*3

For every prime listed, how many are needed to find all numbers?
2: we need three because of 632
3: we need two because of 9
5: we need one because of 420
7: we need one because of 420
79: we need one because of 632.

Therefore, our LCM is:
2*2*2*3*3*5*7*79
= 199,080

It is the smallest number that can be divided by 420, by 632 and by 9.

Answer 7

http://en.wikipedia.org/wiki/Least_common_multiple