(2,5-2\frac{1}{3})^2-(-\frac{1}{3})^3 :\frac{2}{3}=(2\frac{1}{2}-2\frac{1}{3})^2-(-\frac{1}{3})^3 :\frac{2}{3}=(2\frac{3}{6}-2\frac{2}{6})^2-(-\frac{1}{3})^3 *\frac{3}{2}=(\frac{1}{6})^2-(-\frac{1}{18})=\frac{1}{36}+\frac{1}{18}=\frac{1}{36}+\frac{2}{36}=\frac{3}{36}=\frac{1}{12}