My daughter and I both got the answer 3, but her teacher said it's wrong.
2007-08-22 11:01:59 · 11 answers · asked by Emily Dew 7 in Science & Mathematics ➔ Mathematics
Oops! Looks like we confused LCM with LCD! Thanks to all!
2007-08-22 11:12:52 · update #1
It's 126. The reason you got 3 is you did LCD (Least Common Denomanator) this is the lowest number that gos into both what you wanted was the LCM (Least Common Multiple) which is the lowest number they can both multiply into. Generally you can find this out by multiplying the two numbers although this is not always true as in the case of 3 and 6 the answer would be 6. 3*2 and 6*1.
2007-08-22 11:13:23 · answer #1 · answered by Morgan V 1 · 0⤊ 0⤋
LCM is lowest common multiple - the lowest number that both A and B can divide without remainder (e.g. LCM for 6 and 4 is 12)
You are thinking of the LCD - you have taken the lowest number that will divide both 9 and 42.
In this case the LCM is 126 - 126/9=14 and 126/42=3
Easiest way to find it is to break each number down into prime number divisors, remove any common ones (but delete from one side only)
9=3x3 42=7x3x2 - one pair of 3's so drop one of them
multiply remaining factors 3x3x7x2 = 126
2007-08-22 11:18:57 · answer #2 · answered by piscesgirl 3 · 0⤊ 0⤋
So i really want 10 point so ill try to explain like a teacher lol
of course you'll get it wrong because:
***
LCM means Least common multiple
and GCF mean Greatest common factor so u got it wrong because u got GCF to get LCM all you need to do is find all the prime factors of each number. The easiest way to do it is with a factor tree so here:
42= 2 factors=6&7
as 7 is already a prime number u dont need to break it up into prime factors, but as 6 isnt a prime number u should break it up so i broke it up to 2&3
****
so the primes of 42 are 3&2&7
**** now we'll need to find factors of nine its pretty easy because it is 3&3
****
so now is the final step to make it easier we'll combine all 3s together and make a three cubed (srry cant make that sign)
so three cubed is 9 X 2 X 7 = 126
so the answer is 126 there ya go now they all work :)
Do i deserve 10 points???? :P
2007-08-22 11:24:36 · answer #3 · answered by Anonymous · 0⤊ 0⤋
9*42/3 = 9*14 = 126.
To find the LCM of 2 numbers take their
product and divide it by their GCD.
2007-08-22 11:25:08 · answer #4 · answered by steiner1745 7 · 0⤊ 0⤋
The answer is 126
The least common multiple of two or more nonzero whole numbers is the smallest whole number that is divisible by each of the numbers. There are two common methods for finding the least common multiple of 2 numbers.
Find the least common multiple of 9 and 42. We list the multiples of each number:
9: 18, 27, 36, 45, 54, 63, 72, ... 81,90,99,108,117,126...
42: 42, 84, 126, 168, 190, ...
2007-08-22 11:07:39 · answer #5 · answered by originalsmartie 4 · 0⤊ 0⤋
126
2007-08-22 11:05:02 · answer #6 · answered by peteryoung144 6 · 1⤊ 0⤋
126
2007-08-22 11:08:35 · answer #7 · answered by Anonymous · 0⤊ 1⤋
Lowest Common Multiple Of 12 And 42
2017-02-23 09:33:00 · answer #8 · answered by jaideep 4 · 0⤊ 0⤋
9x=y
42z=y
so 9x=42z
x=14
z=3
the answer is 126
2007-08-22 11:14:39 · answer #9 · answered by J 3 · 0⤊ 0⤋
126 is what I get, too.
.
2007-08-22 11:07:04 · answer #10 · answered by tlbs101 7 · 0⤊ 0⤋