round off answer to two

Question

estimate (using scientific notation and rounding each entry to two digits) and round off answer to two digits: (0.000014x10^-12)(849018x10^4)

Answer 1

We have to move the first decimal right 5 digits to make it 1.4 x 10^{-12 + 5} = 1.4 x 10^-7.

 

8.5 x 10^{4 - 5} = 8.5 x 10^-1

 

1.4(8.5) = 11.9 = 1.2 x 10^-1

 

(10^-1)(10^-1)(10^-7) = 10^-1-1-7 = 10^-9

 

1.2 x 10^-9