As we learned in class today, we don't have to write out the factor lists for numbers and then compare them when trying to find the Greatest Common Factor of 2 numbers.
What technique could you use to find the GCF when comparing 2 numbers?  Could you give an example?  (hint: you could write an example, take a picture of your work, then post it as part of your blog if you want)


09/22/2010 4:11pm

i dont get it

09/22/2010 4:11pm

can you please help me??
actually nevermind

Gurnam 807
09/22/2010 4:55pm

You can use a venn diagram and list the common multiples(factor tree). Then, multiply all the common multiples and that's how you find the GCF.

09/22/2010 6:09pm

its easy,
you make a venn and seperate the factors into each section and multiply the middle section to get the GCF...and multiply all the factors overeall to get the LCM. I can't understand it when its in a book but i can understand it in person..
thanks Mr. Dobbie !! :)

09/22/2010 6:13pm

So in general you just multiply the factors that both numbers have in common and thats how yo would get your GCF.
eg: 36 & 48, GCF= 12

09/22/2010 6:44pm

To find the GCF you have to multiply all the numbers in the middle of the ven diagram ,and then you multiply all tfactors to find the LCM.

09/22/2010 7:10pm

To find the GCF you have to multiply all the numbers in the middle of the ven diagram,and then you multiply all the factors to find the LCM.

Japreet 807
09/22/2010 7:17pm

to find the GCF you make a venn diagram and then you multiply all the numbers in the over lapped area.

Parth 807
09/22/2010 8:44pm

I can find the greatest common factor in a venn diagram technique because, when in the venn diagram the middle, first both numbers you see which are common you put those in the middle and the others in the other two circles.After you are done that you multiply the overlaping numbers to find out the greatest common factors.

ex. 48 and 60's GCF is 12 by multiplying the overlaping numbers 3 times 2 times 2 = 12

Twinkle 806
09/22/2010 9:18pm

There are 2 ways to do this....
1. the venn diagram
2. the tree diagram
(i.e; 30 and 45) GCF=15

Simran M 807
09/23/2010 4:06pm

just make a venn diagram of the prime factors. The common factors go in the overlap, multiply those and you have the greatest common factor.

lovepreet g.
09/24/2010 3:55pm

make a venn duagram first
put common factors in the middle, all the factors on the other parts of the venn diagram. for GCF multiply all the common factors. foe LCM multiply every number in the venn diagram

10/04/2010 2:53pm

To find out the geatest common factor and the lowest common multiple all you need to do is make a ven diagram and multiply all the numbers in the middle to find out the GCF and for the LCM multiply all the numbers in the whole ven diagram.

Pawanpreet 806
10/04/2010 2:54pm

A technique that you could use to find the GCF when comparing 2 numbers is, you can use a vindiagram. For example, after you draw your vindiagram you can write on 1 side factors of 48 and in the middle you can write common factors of 48 and 64 and on the other side you can write factors of 64. Then you can mulyiply the common factors to get the greatest common factor.

I also don't know if i'm suppose to tell you which rubric I want, so If I do then can you please tell me.

Sabreena 806
10/04/2010 4:34pm

To find the greatest common factor of 2 numbers we have to make a factor tree for each of the 2 numbers. While doing the factor tree we need to make all of the numbers at the bottom prime, which means the numbers only factors are 1 and itself. Example 2 is a prime number because the only who number that goes into 2 are itself and 1. After we complete the factor tree for both numbers we put the numbers in a venn diagram. If there is the number in the first number and the second number, example, 2 goes into both 24 and 20 you put that number once in the middle circle of the venn diagram. After you do that, you multiply all the numbers in the middle of the venn diagram to get the greatest common factor.

Renu 806
10/04/2010 5:55pm

If we don't want to write out all of the factors of each number and want to find out the GCF of the two numbers all we have to do is make a venn diagram. By doing that it reduces the amount of writing you have to do by listing all of the factors of the two numbers and then comparing them and seeing which is the GCF. To figure out the GCF of two numbers by using a venn diagram you could put the two numbers on the outside of the circle and in the middle a both section. In the both section write all of the factors that are the same from the two numbers and for the other section write down the remaing factors of each number. Then you take the numbers in the both section and you multiply all of those numbers together and you will get your GCF.

If you have 20 and 30
you figure out what the factors are of each number and the same factors go into the both section and then you mupltiply all of the numbers in the both section and you will get the GCF.

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