# How do you write 0.00081 in scientific notation?

Dec 17, 2015

$\textcolor{w h i t e}{\times \times \times \times \times \times \times \times \times .} 8.1 \times {10}^{- 4}$

$\textcolor{b l u e}{\text{It is very important that you look at the method!}}$

#### Explanation:

Your objective is to change the given number so that you have a whole number that is between but excluding 0 and 10 followed by the decimal point.

This introduces an error in that the number you have changed it to is no longer the same value as the one you started with. So you have to include something that would change it back if it were to be applied.
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$\textcolor{b l u e}{\text{Given : } 0.00081}$

$\textcolor{b r o w n}{\text{Some people tell you to move the decimal point. This is not the best}}$
$\textcolor{b r o w n}{\text{way to think about it as it may give the wrong answer in some cases.}}$

$\textcolor{g r e e n}{\text{Keep the decimal point where it is but slide the number to give :}}$

$\textcolor{w h i t e}{\times \times \times \times \times \times \times \times \times .} 8.1$

to change this back to the original number you would need to apply:

$\textcolor{w h i t e}{\times \times \times \times \times \times \times \times \times .} \frac{8.1}{{10}^{4}}$

Write this as:

$\textcolor{w h i t e}{\times \times \times \times \times \times \times \times \times .} 8.1 \times {10}^{- 4}$