Finding a common denominator<span> makes it possible to add two fractions because it allows us to </span>write each<span> fraction as a multiple of a </span>common<span> (usually smaller) fraction. Subtracting fractions works the same way; find a </span>common denominator<span> so that the fractions involved are in the same terms. <span> </span>[ Source: </span><span>www.mathmistakes.info/facts/AlgebraFacts/learn/fr/add.html ]</span>
