If two or more fractions have different denominators, it is possible to write them with a common denominator. As an example, consider $\frac{1}{3}$ and $\frac{1}{2}$ . $$\frac{1\cdot 2}{3\cdot 2}=\frac{2}{6}\text{and}\frac{1\cdot 3}{2\cdot 3}=\frac{3}{6}$$