It is not necessary to have a common denominator when multiplying fractions. To multiply fractions with different denominators, you multiply the numerators with each other and then the denominators with each other. The end product of multiplying fractions with no common denominator may not be in its lowest terms however, and might need to be reduced. For example, if you were to multiply 1/2 by 2/3, you would first multiply the numerators (1 and 2) to get 2, and then the denominators (2 and 3) for a product of 2/6. After getting this product, reduce it to its lowest terms, end up with 1/2 by dividing both the numerator and denominator by 2, and end up with 1/3 as a final product. Thus, it is not necessary to have common denominators when multiplying fractions.
