Q.Perform each of the following calculations. Round off your answers to two digits. a. $\dfrac{1}{3.40 \times 10^{24}}$ b. $\dfrac{33}{9.00 \times 10^{-4}}$ c. $\dfrac{1.4 \times 10^9}{(2.77 \times 10^3)(3.76 \times 10^5)}$ d. $\dfrac{(4 \times 10^{-3})(9.9 \times 10^{-7})}{(789)(1.002 \times 10^{-10})(0.3 \times 10^2)}$

a. $\dfrac{1}{3.40\times10^{24}} = 0.2941\times10^{-24} = 2.941\times10^{-25}$, rounds to $2.9\times10^{-25}$.

b. $\dfrac{33}{9.00\times10^{-4}} = 3.667\times10^4$, rounds to $3.7\times10^4$.

c. Denominator $= (2.77\times10^3)(3.76\times10^5) = 10.415\times10^8 = 1.0415\times10^9$; $\dfrac{1.4\times10^9}{1.0415\times10^9} = 1.344$, rounds to 1.3. …

Carry out each division/multiplication in scientific notation (combine coefficients, add/subtract exponents as appropriate), then round …

• Losing track of a negative exponent sign midway through a multi-step calculation (especially in part d, with three exponents to combine). …