# Question #2707b

Feb 6, 2015

$45 m i l l i o n t h = \frac{45}{\text{1 million}} = 0.000045$

In scientific notation, you move the decimal point to the left or right, untill you have one proper (=non-zero) digit on the left of the decimal point.

In this case it would be $4.5$ with 5 moves to the right.

Now the notation works like this:
To the right:
You add $\cdot {10}^{\text{-moves}}$ (negative power)
To the left:
You add $\cdot {10}^{\text{+moves}}$ (positive power)

So in your case it would be $4.5 \cdot {10}^{-} 5$

If we had a number like 45 million:
$45000000 = 4.5 \cdot 10000000 = 4.5 \cdot {10}^{7}$