Question

Simplify the below expression: (you may use a calculator)(3.5 . 10-3) - (4.0 . 10-4)A) 0.5 . 10-7B) 0.5. 10C) 3.1 . 10-3D) 3.1 . 10-1E) I don't know.

Answer 1

Use a calculator to find the value of the following expression:

`(3.5*10^(-3))-(4.0*10^(-4))`

The result is:

`3.1*10^(-3)`

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:

`4.0*10^(-4)=0.40*10^(-3)`

Then:

`(3.5*10^(-3))-(4.0*10^(-4))=(3.5*10^(-3))-(0.40*10^(-3))`

Since both numbers have the same power of 10, we can add or substract them as we normally would:

`3.5*10^(-3)-0.40*10^(-3)=3.1*10^(-3)`