Wahts the gcf and lcm of 18 and 30
1 answer:
Hey there. So first, to work out the LCM, we need to find the multiples of 18 and 30. We’ll start with 18, and we’ll stop at a reasonable number.
18, 36, 54, 72, 90.
30, 60, 90, 120.
Already we notice that 90 is the smallest multiple that is evident in both numbers. So 90 is your LCM.
Now for the GCF, we want to begin by creating a factor tree for 18 and 30. I found one on the internet so it’s easier to view.
When finding the GCF, you want to circle all the prime numbers you have, so in this case, for 18, we have 2 x 3 x 3. They’re all prime.
For 30, we have 2 x 3 x 5. They’re all prime.
If we now circle the numbers that are common in both so we have (2) in 18 and 30, and we have (3) in 18 and 30. We are left with 5 and 3, ignore them for now. Because we managed to circle 2 and 3, if we multiply them together, we get 6. So the GCF of 18 and 30 is 6. And the LCM of 18 and 30 is 90.
Sorry if this sounds confusing, i tried my best.
18, 36, 54, 72, 90.
30, 60, 90, 120.
Already we notice that 90 is the smallest multiple that is evident in both numbers. So 90 is your LCM.
Now for the GCF, we want to begin by creating a factor tree for 18 and 30. I found one on the internet so it’s easier to view.
When finding the GCF, you want to circle all the prime numbers you have, so in this case, for 18, we have 2 x 3 x 3. They’re all prime.
For 30, we have 2 x 3 x 5. They’re all prime.
If we now circle the numbers that are common in both so we have (2) in 18 and 30, and we have (3) in 18 and 30. We are left with 5 and 3, ignore them for now. Because we managed to circle 2 and 3, if we multiply them together, we get 6. So the GCF of 18 and 30 is 6. And the LCM of 18 and 30 is 90.
Sorry if this sounds confusing, i tried my best.
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