Question

9.9×10^-3 how do we get that before standard form

Answer 1

The power of 10 shows how many digits it are necessary to run the decimal point

$\begin{gathered} 9.9\ast10^{-3}\text{ (Move the decimal point }3\text{ to the left)} \\ 9.9\ast10^{-3}=0.0099 \end{gathered}$