Question 1202125:  4 digit number license plates can be made if:
 
first digit cannot be zero and repetition is not allowed. 
 Answer by Shin123(626)      (Show Source): 
You can  put this solution on YOUR website! There are   choices for the first digit, since it can't be zero. For the second digit, you can't pick the same one as the first digit, so there are   choices. For the third digit, you can't pick the same one as the first or second digits, so there are   choices. For the last digit, you can't pick the same one as the first, second, or third digits, so there are   choices. In total, there are   possible license plates. 
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