Simplify $\left[\left\{{\left(\frac{-2}{5}\right)}^{-7}\times {\left(\frac{-2}{5}\right)}^9\right\}÷{\left(\frac{-2}{5}\right)}^2\right]$ and express the result as a power of $5$.

Simplify $\left[{\left(-\frac{1}{3}\right)}^8÷{\left(-\frac{1}{3}\right)}^5\right]-\left[{\left(-\frac{1}{3}\right)}^5÷{\left(-\frac{1}{3}\right)}^3\right]$

Simplify ${\left(2^{-1}÷5^{-1}\right)}^2\times {\left(\frac{-5}{8}\right)}^{-2}$

Write the following numbers in scientific notation:$0.00002$​​​​​​

Write the following numbers in scientific notation:$0.00000542$​​​​​​

Write the following numbers in scientific notation:$0.000000093$​​​​​​

Write the following numbers in scientific notation:$0.003142$​​​​​​

Write the following numbers in standard form:$6\times {10}^{-5}$​​​​​​

Write the following numbers in standard form: $5.32\times {10}^{-4}$​​​​​​