SOLUTION: how many different 4 digit numbers can be created if no digit can be repeated? Remember a number cannot begin with 0

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Question 236655: how many different 4 digit numbers can be created if no digit can be repeated? Remember a number cannot begin with 0
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
First digit 1 of 9 (excludes 0 thus 1,2,3,4,5,6,7,8,9 = 9 options.
Second digit 1 of 9 (includes 0) thus 0 plus 8 of the remaining 9 = 9 options.
Third digit 1 of 8 total of 10 digits minus the 2 already used = 8 options.
Fourth digit 1 of 7 total of 10 digits minus the 3 already used = 7 options.
9*9*8*7=4,536 different numbers.