# How do you write 0.00000000129 in scientific notation?

##### 1 Answer

Write down the "value" of the digits, then the number of places the decimal moved to make it happen and in this case you get

#### Explanation:

Scientific notation is all about telling someone 2 important bits of information: the "value" of a number - such as the digits 129 in this example, and just how many 0's are before or after it.

The value of a number will never be less than 0 and never more than or equal to 10.

So let's figure out the value - 129 is the digits we want to work with. We put the decimal point after the first digit of the value - so in this case it's 1.29.

Now let's tell people what the difference is between 0.00000000129 - the number we want to express and 1.29 - the value in our scientific notation.

We use a notation of

Now the question is how far away from 0.00000000129 from 1.29. If I'm counting right, the decimal needs to move 9 places to the right to get from 0.00000000129 to 1.29. So 0.00000000129 is 9 decimal places smaller than 1.29. So using the notation above, it's

Putting it all together, the scientific notation of 0.00000000129 is a combo of the value and the number of places the decimal moved: