Answer:
(850000) - (9.0 × 10^5) calculated with significant figures is -0.5 × 105, which contains 1 sig figs and 1 decimals. There are 2 steps to calculate (850000) - (9.0 × 10^5) with sig figs. To count the number of sig figs in -0.5 × 105, strip the leading insignificant digits (-0.) to get the significant digits (5).
ANswer is 1 (-0.5e5)