To the power means relates to the exponents. So for example,
In your question 4 to the power of 2 is
and 4 to the power of 10 is
So to divide, it is
Following the exponent rules that you learned, we subtract the indexes (since they have the same base)
Not sure why you did 10-8, but I think you had the right idea. You just subtracted the exponents wrong.