oh yeah, so the cubed root is pretty much instead of finding the square root of something (like how sqares are 2 dimensions and you find which number multiplied by itself equals what you are trying to find) the cubed root is just replacing the 2 with a 3. so you would find which number multiplied by itself 3 times equals the main number.
all you need to do is find the volume of those cubes, and then put it into scientific notation (you know, 10 with an exponent multiplied by another number, stuff like that)
I'm so sorry if my explanation is a little all over the place, I hope this helps you out though