Let us try another example.
How many different license plates are available if each plate contains a sequence of 3 letters followed by 3 digits?
There are 26 choices for each of the three letters and 10 choices for each of the three digits. Therefore, by the multiplication principle, there a total of 26, times 26, times 26, times 10, times 10, times 10 possible sequences. The product is 17 576 000. Therefore there are 17 576 000 possible license plates.