Hello!
Order of magnitude of a measure is an estimate of the base power 10 closest to a given measure.
The scientific notation (N) of 0.000000000333 (x), being (number of decimal places) y, knowing that the scientific notation according to the rule of scientific notation, before the comma can only have the numbers 1 to 9, let's see:



note: Moved 10 decimal places to the right negatively
I Hope this helps, greetings ... DexteR! =)