i dont know what to do with the number 3.2 in this problem trying to obtian the loudness of a sound in decibals. I already did some of the steps

$\displaystyle 10log(3.2* 10^{-5}W/m^{2}-10^{-12}W/m^{2})$ I just dont know what to do with the 3.2 in the equation. Only have done problems that use $\displaystyle 1.0* 10^{n}$ And with 1.0 the answer would be $\displaystyle 10^{7}$ or 70 dB