TITLE: What does the small number on top of the square root symbol mean?
QUESTION [14 upvotes]: I just came across this annotation in my school's maths compendium:

The compendium is very brief and doesn't explain what this means.

REPLY [3 votes]: $\sqrt[n] a$=$a^ \frac 1 n$
Also,if $\sqrt[n] a$=$x$ then $x^n=a$