Answer
$\frac{3}{64}$
Work Step by Step
1. Take the reciprocal of both fractions due to negative exponents which will give you $\frac{1}{4^2}-\frac{1}{4^3}$
2. Find the least common denominator to add the fractions which will give you $\frac{4}{64}-\frac{1}{64}$
3. Subtract the fractions which will give you $\frac{3}{64}$
