Teaching kids LCM and GCF with the ladder method requires you to start by writing out all of the numbers on a line. Teach kids LCM and GCF with the ladder method with help from a professional private tutor in this free video clip.

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Teaching kids LCM and GCF with the ladder method requires you to start by writing out all of the numbers on a line. Teach kids LCM and GCF with the ladder method with help from a professional private tutor in this free video clip.

Part of the Video Series: Math Concepts

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Hi, I'm Rachel Kaplove, and today we're going to be going over how to teach LCM and GCF using the ladder method. Let's look at the numbers 24 and 36. So now we want to find the LCM and the GCF. Start off by writing the numbers on one line like this. Then make an L. Ladder method. Now we're going to find the smallest prime number that goes in to these two numbers. In this case it's two. The smallest prime number. So we have two in to 24 is 12 and we have two in to 36 is 18. Then we do it again until we have all prime numbers. So we make another L. Again the smallest prime number is two. So we divide two in to 12 to get six. We divide two in to 18 to get nine. Again we make the L. Now the smallest prime number that goes in to six and nine it's not going to be two it's going to be the next one. Three. Divide six by three to get two. Divide nine by three to get three. Now we have all prime numbers so we know that we finished. We're at the end. To find the LCM we make an L. We multiply all these numbers together on the L. So LCM is going to be two times two times three times two times three. Which all together is 72. The GCF you find by going straight down this line. That's going to two times two times three. Four times three is 12. And that is how you find LCM and GCF using the ladder method. I'm Rachel and thanks for learning with us today.