Answer
$$\frac{1}{72}$$
Work Step by Step
$Evaluate$ $the$ $expression:$
$$2^{-3}-3^{-2}$$
$$2^{-3}-3^{-2} = \frac{1}{2^3}-\frac{1}{3^2}$$
$$\frac{1}{2\times2\times2}-\frac{1}{3\times3}$$
$$\frac{1}{8}-\frac{1}{9}$$
Find the least common denominator [72]
$$\frac{1\times9}{8\times9}-\frac{1\times8}{9\times8}$$
$$\frac{9}{72}-\frac{8}{72} = \frac{1}{72}$$
