6 x 10^-6/ -3 x10^0
$$\frac{6\times10^{-6}}{-3\times 10^0}\\\\ =\frac{6\times10^{-6}}{-3\times 1}\\\\ =-2\times10^{-6}\\\\$$
(6 x 10^-6) / (-3 x 10^0)
= -2 x 10^-6