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$Adding and subtracting fractions by finding a common denominator$

Adding and subtracting fractions by finding a common denominator

When the denominators are unequal, we have to find a common denominator before we can add or subtract the fractions. To find a common denominator, we need to find the least common multiple (LCM) of the denominators. Then we can use the LCM as our common denominator. In fact, we call that the “least common denominator,” because it’s the smallest common denominator we can use.

Factoring to find common denominators for rational expressions

To add rational expressions, you need to find a common denominator, just like when you add fractions in which the numerator and denominator are just numbers. The difference is that finding the common denominator of rational expressions can be more complicated because their denominators can include variables.

Learn mathKrista KingApril 24, 2019math, learn online, online course, online math, rational expressions, common denominator, factoring, factoring for a common denominator, factoring to get a common denominator, algebra, algebra 1, algebra i, rational functions