Monetary notation

If I have understood correctly in Europe when writing an amount of money the use of the comma and period are different then they are here in the US. In the US we would write that one thousand dollars like 1,000.00 whereas in Europe it would be 1.000,00.

  1. Where does this difference come from?
  2. Does it affect notation in science? (i.e. 1.45 L)
  3. Hi Opal!