Use a calculator to find the value of the following expression:
[tex](3.5\times10^{-3})-(4.0\times10^{-4})[/tex]The result is:
[tex]3.1\times10^{-3}[/tex]Therefore, the correct option is C) 3.1 * 10^-3
To get this result, first write both numbers using the same power of 10.
Move the decimal point to the right to add 1 to the power of 10 on the second term:
[tex]4.0\times10^{-4}=0.40\times10^{-3}[/tex]Then:
[tex](3.5\times10^{-3})-(4.0\times10^{-4})=(3.5\times10^{-3})-(0.40\times10^{-3})[/tex]Since both numbers have the same power of 10, we can add or substract them as we normally would:
[tex]3.5\times10^{-3}-0.40\times10^{-3}=3.1\times10^{-3}[/tex]