EDIT: There are 727 numbers that are 3 digits numbers such that none of the digits are repeated. For the first digit, you have 9 choices (digits 1 -9) you don't want zero as the first digit.------------------------------------ 727 numbers
There are 648 numbers that are 3 digits numbers such that none of the digits are repeated. For the first digit, you have 9 choices (digits 1 -9) you don't want zero as the first digit.
