Lesson goal: Finding common denominator of two fractions using the LCM

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The primary use of the LCM in math is in finding a common denominator of two fractions, in order the add or subtract them. That's right, the common denominator of two fractions IS the LCM of the two denominators.

This means if you knew the denominators of two fractions you are trying to add, the LCM of the two denominators will be the common denominator. The lesson here will show you how to use the LCM in this way.