In setting a 3-digit combination to a lock where the digits cannot be zero and cannot be repeated, how many possible combinations are there?

Flashcard 6 - Math Flashcard Set for the PSAT/NMSQT Exam

9 x 8 x 7 or 504

There are 9 possible numbers for the first digit, 8 possible numbers for the second digit, and 7 possible numbers for the third digit:

9 x 8 x 7 = 504

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