.4^{3}-.7^{3}-.3^{3}= what and how to do it
Use a calculator or solve by hand. To solve by hand, I find that it helps to write each decimal into a fraction and then recall the fact that $\displaystyle (\frac{a}{b})^n = \frac{a^n}{b^n}$
For example, $\displaystyle (.4)^3 = (\frac{4}{10})^3 = \frac{4^3}{10^3} = \frac{64}{1000}$ The process is similar with the other decimals in this formula. then it's a simple matter of addition and subtraction of fractions.