A spinner with 6 equally sized slices has 2 blue slices, 1 yellow slice, and 3 red slices. The dial is spun and stops on a slice at random. What is the probability that the dial stops on a slice that is not blue?

Write your answer as a fraction in simplest form.

There are a total of 6 slices on the spinner. Since 2 of them are blue, the other 4 slices must not be blue. Therefore, the probability that the dial stops on a slice that is not blue is 4/6, which simplifies to 2/3. Therefore, the answer is $\boxed{\frac{2}{3}}$.