$\begin{align}  & \frac{910/9\times {{10}^{-33}}kg}{\mu g}=\frac{910/9\times {{10}^{-33}}\times {{10}^{3}}}{{{10}^{-6}}}=910/9\times {{10}^{-24}} \\  & =9/109\times {{10}^{-24}}\times {{10}^{2}}=9/109\times {{10}^{-22}} \\ \end{align}$