Place a decimal between the first digit 3 and the second digit 3.
Now how many spots to the left must the decimal move to go from the number to the number ?
The decimal needs to move 3 places to the left. So this is equivalent to multiplying by to move the decimal 3 places to the left. Notice how the exponent -3 corresponds to the number of spots the decimal needs to move.
So putting all of this information together, we get
This means that the number in scientific notation is
In other words,
So this also means that the approximate value for is