Question

How do you write the number $0.000000009$ in scientific notation?

Answer 1

Write the given number in scientific notation:

Given that the number $0.000000009$

Scientific notation is in the form $a\times {10}^b$ where $1\le a<10$ and $b$ is an integer in power.
Move the decimal point to the right to create a new number from $\mathbf{1}$ up to $\mathbf{10}$.

$$\begin{gathered} \Rightarrow 0.000000009 \\ \Rightarrow a=9 \end{gathered}$$

The number of decimal places you move will be the exponent on the $\mathbf{10}$.

$\Rightarrow 9\times {10}^b$

Count the number of times you moved the decimal point.

$\Rightarrow b=9$, this will be the power term.

Moving the decimal point to the right, the exponent is negative.

$\Rightarrow b=-9$

So, the scientific notation will be $9\times {10}^{-9}$.

Hence, the scientific notation of the number $\mathbf{0}\mathbf{.}\mathbf{000000009}$ is $\mathbf{9}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{9}}$.