help!!!!!!!!! math problem

M13

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Nov 8, 2004
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How do you find 2 numbers that have a LCM of 35 and a GCF of 7??
Thanks very much for helpful responses!!!!!!
 

M13

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Nov 8, 2004
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That is the whole problem.
It reads: Find a pair of numbers for each set of conditions
The LCM is 35
The GCF is 7
 

M13

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Nov 8, 2004
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type your post into Google and you your answer.

Does not compute.
I do not understand how that helps. Please explain
 

M13

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Nov 8, 2004
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you're talking about fractions right?

the LCM is 35...... since 35 is the common denominator

so whatever was above the 7 in the fraction multiply it by 5

also it would be better if you show the whole problem

No, it is Least Common Multiple and Greatest Common Factor
 

M13

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Nov 8, 2004
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I am sorry but the web link does not tell me how to work the numbers if they are unknowns. I think the answer is 35 and 70 because if the LCM is found by taking the 2 numbers and dividing them by the GCF but it still doesn't quite work out properly.
 

Soccer55

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Jul 9, 2000
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How about 7 and 35 themselves? The prime factorizations are 35=5*7 and 7=7. The GCF is 7 and the LCM has to be 35. Seems kind of silly to have the numbers given in the problem be the answer, but it appears to work.

-Tom
 

Soccer55

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Jul 9, 2000
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Originally posted by: M13
I am sorry but the web link does not tell me how to work the numbers if they are unknowns. I think the answer is 35 and 70 because if the LCM is found by taking the 2 numbers and dividing them by the GCF but it still doesn't quite work out properly.

I thought that at first, but 35=5*7 and 70=2*5*7 which means that the GCF is 5*7=35.

-Tom
 

M13

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So then the answer is that the LCM and the GCF are the 2 numbers asked for? So would it follow that if the LCM is 36 and the GCF is 1 then the 2 numbers would be 1 and 36??
 

desteffy

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Jul 16, 2004
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Originally posted by: Soccer55
How about 7 and 35 themselves? The prime factorizations are 35=5*7 and 7=7. The GCF is 7 and the LCM has to be 35. Seems kind of silly to have the numbers given in the problem be the answer, but it appears to work.

-Tom

This is correct
 

yoda291

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Aug 11, 2001
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think about it.

GCF is the product of all common factors. 7 is a prime number. ergo it is a product of 1 and 7. so the first number is trivially easy to find. Now list out multiples of the first number until you get one that is a factor of 35.

Don't give your kid the answer tho. It completely defeats the point of homework.
 

Soccer55

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Jul 9, 2000
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Originally posted by: M13
So then the answer is that the LCM and the GCF are the 2 numbers asked for? So would it follow that if the LCM is 36 and the GCF is 1 then the 2 numbers would be 1 and 36??

In this case, yes, I would say that it is the 2 numbers asked for. However, that is not always the case. Consider 24 and 36. The prime factorizations are 24=2*2*2*3 and 36=2*2*3*3. So the GCF is 2*2*3=12 and the LCM is 72 as 3*24 = 2*36 is the first combination of x and y in the equation 24x=36y that will give you an equality.

-Tom
 

fornax

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Jul 21, 2000
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Soccer55 got it right. The LCM is 35, so the numbers are either 5 or 7 (both are primes so there's no other choice). And only 7 is divisible by 7 (5 is not), therefore the answer is 7 and 35.
 

M13

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Nov 8, 2004
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So as I asked before, then if the LCM is 36 and the GCF is 1, then the 2 numbers will be 36 and 1?
By the same token, if LCM is 120 and gcf is 10, the 2 numbers are 120 and 10?
 

M13

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OK, thanks very much for your help and insight. I need to ask the teacher if she truly did explain the factoring concept in her class.