Let's use 304,900,000 as an example.
In scientific notation it is 3.049 x 10^8
When converting to scientific notation, just drop any zeros at the end of the number and put the decimal place after the first digit. Then for the power on the 10, count all the digits (including zeros). In our example there are 8 digits after the 3 so we raise 10 to the 8th power.
Now let's look at small numbers. For example, 0.0000718
If the number is between 0 and 1, we will raise the 10 to a negative power. In this case the answer is 7.18 x 10^-5.
What you do to find the power is move the decimal point over so that there is one digit in front. Just like we did with the first example. Count how many places the decimal moved and use it for the power.
Hopefully this helps. Let me know if you need further explanation :)
