In adding and subtracting fractions with unlike denominators, you have to get a least common denominator which is exactly like the least common multiple it just so happens to be in the denominator.

NEW YORK--(BUSINESS WIRE)--Common Denominator (formerly known as Top Honors), a New York City-based non-profit that provides free 1:1 math tutoring to middle-schoolers from the city’s underserved ...

In almost every equation, one can find a common denominator. Although it may seem a bit counterintuitive, even opposites have something in common. Consider how the cultures of middle Eastern countries ...

“Who would draw a picture to divide 2/3 by 3/4?” asked Marina Ratner, a professor emerita of mathematics at the University of California at Berkeley, in a recent Wall Street Journal opinion piece.