ABC Family: Whitewolf144 OT: I need some homework help, can anyone here tell me how to find LCM using prime factorization?

OT: I need some homework help, can anyone here tell me how to find LCM using prime factorization?

Posted Sun, 12/07/2008 - 23:44 — Whitewolf144

the part im having problems with is when you multiply all the multiples together and there is more than 1 of a number like heres an example:
find the LCM of 75, 500, 90.
the multiples of 75 are 5x5x3 ,the multiples of 500 are 2x2x5x5x5 ,and the multiples of 90 are 2x5x3x3
the part im having trouble with is when you multiply them together but dont repeat the numbers once you have them up and it has exponents.
can someone PLEASE help me ?

ps: if theres not enough information to tell you what my problem is just say so and ill put it up in more detail i just dont know how to word it.

Kyle XY

Tue, 12/09/2008 - 15:23 — Whitewolf144

thanks guys (I finally figured it out)

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Mon, 12/08/2008 - 09:22 — dawn4scifi

This forum is fun. A discussion area, a class room, a political arena, a church... Except when people are deliberately nasty or argumentative for the sake of arrogance, I love this place.

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Mon, 12/08/2008 - 15:59 — Cnith

there's a reason I suck at math... looking at all of those numbers gave me a headache! And I'm sure it was a simple concept...but seeing like that makes my eyes spin!

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Mon, 12/08/2008 - 07:20 — nycscififan

Find the LCM of 75, 500, 90:

Multiples are:
75 = 3x5x5 = 3 * (5²)
500 = 2x2x5x5x5 = 2² * 5³
90 = 2x5x3x3 = 2 * 3³ * 5

In looking at these, you can see that they all have the number 5 in common, so that is the least common multiple. It's simply the multiplier that they all have in common. 3 is NOT an LCM because 500 does not use it and 2 is NOT an LCM because 75 doesn't use it.

To change a set of multipliers into exponential format, just count the number of times the number is used to get the exponent. 2x2x2 = 2³

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Mon, 12/08/2008 - 02:00 — Watcher50

I did a search for:

"LCD and factorization". It found these. Check 'em out. somethings gotta work.

#
Factoring - Least Common Multiple (LCM) - First Glance
The least common multiple (LCM) of two numbers is the smallest number (not zero) ... Homework Help | Pre-Algebra | Factoring, Email this page to a friend ...
http://www.math.com/school/subject1/lessons/S1U3L3GL.html
#
LCM and GCF
Find the GCF and LCM of 3, 6, and 8. First I factor the numbers and list their prime factorizations:. listing of factors. Then my GCF and LCM are given by: ...
http://www.purplemath.com/modules/lcm_gcf.htm
#
Untitled Document
The least common multiple of a ... Find the LCM of 12, 20, and 54. Sol: Find the prime factorization of each number and ...
http://www.nvcc.edu/alexandria/science/math/mathproject/More/LCM/lcm.h…
#
GCF and LCM by Prime Factorization - Math
A straight forward way to find the greatest common factor (GCF) and least common multiple (LCM) using prime factorization. Article includes examples and ...
http://www.bellaonline.com/articles/art13334.asp
#
TutorTemplate
One way to find the LCM is to find the prime factorization of each number and take each prime the greatest number of times it occurs.
http://math.stcc.edu/MathTutor/lessons/Pre31a.htm

--watcher

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The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. --George Bernard Shaw

Mon, 12/08/2008 - 01:30 — Whitewolf144

you have to take out numbers that are the same like both 500 and 90 have several 2s so you have to take away the numbers that are factors of the numbers i just dont know how many to take out

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Mon, 12/08/2008 - 01:43 — Watcher50

I did a search for:

"LCD and factorization". It found these. Check 'em out. somethings gotta work.

--watcher

—

The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. --George Bernard Shaw

Mon, 12/08/2008 - 01:27 — Watcher50

Here is yer ANSWER.
It should work.
www.bellaonline.com/articles/art13334.asp
--Watcher

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The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. --George Bernard Shaw

Mon, 12/08/2008 - 00:25 — Cnith

I don't even know what that is!! I'm so sorry!

Can you try restating the question again please? I'm not sure what you mean by 'don't repeat the numbers once you have them up' part....

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After my picture fades and darkness turns to grey...
If you're lost, you can look and you will find me.
Time after time...

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Kyle XY

OT: I need some homework help, can anyone here tell me how to find LCM using prime factorization?