It's hard to explain how to get this and I don't really know myself but you can just try options on you calculator and enventually you should get one that = 2, for example I tried 32^1/6 and it wasn't quite right, then i tried 1/5 and it did equal 2 so it is right.
A bit of logic behind the answer is 2 x 1 = 2 and 2 x 2 x 2 x 2 x 2 (timesing 2 five times) = 32 so therefore 1/5!