Least Common Multiple (LCM) & Greatest Common Factor (GCF)

But since 60 is the smallest common multiple, 60 is the Least Common Multiple. i.e. LCM = 60. Why must I learn how to find the LCM? The LCM is what makes up the least common denominator needed to add fractions. For example, if we add the fractions below, we need a common denominator. The least common denominator will be 20, the LCM of 5 and 4. ................
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