if it is not contained in a fraction write it as one over the variable with a positive exponent
ex. 2^-1 = 1/2. 3^-2 = 1/3² = 1/9
if it is in the denominator of a fraction move it to the numerator and make it positive
ex. 1/4^-1 = 4. 2/3^-2 = 2*3² = 18
if it is in the numerator...you get the picture
ex 6^-2/3 = 1/3*6² = 1/108
hope that helps