On this you are really just trying to find the lowest number that both of the numbers go into. For example if you have the numbers 6 and 9, 18 would be the lowest common multiple because it is the smallest number that both the numbers go into. An example with fractions is 3/4 and 5/6, what they are trying to tell you is that you find a common denominator for the two fractions (here it would be 12, making them 9/12 and 10/12) and then you can add them together to get the least common multiple (for this problem it would be 19/12). This is a faster way that works for fractions, but would not work as well in my opinion for whole numbers.