Answer
(a) $ 1.4598 \times 10^2$
(b) $ 3.2 \times 10^2$
(c) $ 6.2 \times 10^{-3}$
(d) $9.9 \times 10^{10}$
Work Step by Step
(a) $ 145.75 + 0.23 = 145.98 = 1.4598 \times 10^2$
(b) $79500/(2.5 \times 10^2) = \frac{79500}{2.5} \times 10^{-2} = 32000 \times 10^{-2} = 3.2 \times 10^2$
(c) $70 \times 10^{-4} - 8.0 \times 10^{-4} = 62 \times 10^{-4} = 6.2 \times 10^{-3}$
(d) $1.0 \times 9.9 \times 10^{10} = 9.9 \times 10^{10}$