Factors and Greatest Common Factor (GCF)

Doing factors are very easy if you really know your multiplication. The process of "factor trees" or mainly called prime factorization. Prime factorization takes one large number and divide it into smaller numbers. Then take those smaller numbers and divide them into even smaller numbers. Then if you can take those numbers and divide into smaller numbers. If you can't divide those numbers they are prime and the tree ends. This is an example of one.

80
10 8
5 2 2 4
5 2 2 2 2
(To make the primes look better, make the most shown number and make it into exponents to make it look like this, 5 x 24)Pretty easy once you know it well. Now I will teach you how to do the GCF, or greatest common factor. The greatest common factor is the greatest common factor between two or more numbers. Pretty confusing, but it should look like this.

List all factors of both numbers
24:1,24,2,12,3,8,4,6
48:1,48,2,24,3,16,4,12,6,8
GCF:24

or

24
48:1,48,2,24,3,16,4,12,6,8
Take the biggest number and find the factors of that number.
Then see if the biggest factor goes in the other number(s)

Quite simple if you know your multiplication. Here is some key vocabulary.

Factor: A multiplier that multiplys another number.
Prime Factorization: Taking a big number and finding the prime factors.
Greatest Common Factor: The greatest factor shared between two or more numbers.

For more examples or problems on how to do GCF, go to http://go.hrw.com/math/midma/gradecontent/loadlesson.html?course=c2&chapter=2&lesson=5&SE=1&sz_audio=1&calc=1&state=xx&actCourse=0

For more examples or problems on Prime Factorization, go to http://go.hrw.com/math/midma/gradecontent/loadlesson.html?course=c2&chapter=2&lesson=4&SE=1&sz_audio=1&calc=1&state=xx&actCourse=0

For reasons why to do Prime Factorization, go to http://www.mathmojo.com/interestinglessons/why_learn_prime_factors/why_learn_prime_factors.html

(I would use a link to show you why GCF is used, but there are no examples, sorry)

Both very simple, but very hard if being used on bigger numbers. See you later!