Typing radical other than square and cube root

I am wondering the same thing.  If you have figured it out, Sam Luu, please post on here as a comment how to do it.

Sheila,

Since no one responded, I google searched and found out that you can input other roots.  Just click on the cube root button, then change the index of the radical "3" to what ever number you want.

I know, it is very unintuitive and I wish Khan Academy either add another button and label it "nth root" or replace the cube root button with just the "nth root" button.

Hope that helps.