How do you use a division ladder to find the LCM?

Answer 1

First you write down the numbers you are given and put them on an upside-down long division symbol. Divide the two together until you get to where you cannot divide any longer. Take the right side and bottom numbers and multiply them. This should be your LCM. If you cannot divide them at the first division, use the Listing Method, which is listing some of the multiples of that number and see which one is the smallest same number.

Hope this helped.

Answer 2

If you already know the ladder method, the LCM can be found by multiplying all of the numbers outside of the L's together. If you don't know the ladder method, it will be particularly difficult to draw it in this format. There are many fine videos online that show this method.

All of the "methods" for finding the LCM (ladders, rainbows, trees, fireworks, lattices, cakes, etc.) are just different ways of notating the same process: finding and combining the prime factorizations of the given numbers. Consider 30 and 42. Factor trees are easier to notate here.

30

2,15

2,3,5

42

2,21

2,3,7

2 x 3 x 5 = 30

2 x 3 x 7 = 42

To find the GCF, select the common factors.

2 x 3 = 6, the GCF

To find the LCM, select the highest amount of each factor.

2 x 3 x 5 x 7 = 210, the LCM

If you were using the ladder method, the 2 and the 3 would be on the left side and the 5 and the 7 would be on the bottom.

Answer 3

all you have to do is find the "least common multiple" witch is also the leats common denomenator