Hi Cassia.

Take a look at Brennan's reply to you yesterday.

In it, he talks about the denominator of the exponent corresponding to the digit inside the "notch" of the radical (when nothing is written in the notch, that means a 2 is assumed there).

So

Now if you want to add fractions, you know you need a common denominator, right? It is similar with fractions in exponents. A similar question to yours would be to "radicalize" a^1/2b^2/3. If I want it under one radical sign, I need to make the denominators match:

Hope this helps you,
Stephen La Rocque.