This factors worksheet is great for practicing finding the Least Common Multiple and Greatest Common Factor of number sets. Understanding LCM's and GCF's are very important for working with fraction problems. YOu may select either 2 or 3 numbers for each set. The problems may be selected from four different number ranges. The easiest keeps the number set not greater than 30, and the hardest will keep the number sets not greater than 120. This factors worksheet will generate 10 or 20 LCM and GCF problems per worksheet, and remember every time you create a worksheet the problems will change and will not repeat.