Question 1173431
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Hi
9 numbers:  0,1,2,3,4,5,6,7,8
 How many ways can Two-digit numbers be formed:
 1st digit  8 choices (not 0)
 2nd digit  9 choices  (all)
   8x9 = 72 the ways can Two-digit numbers be formed from the digits above
Repeating of digits are not allowed (11,22,33,44,55,66,77,88)
  72-8 = 64  the ways can Two-digit numbers be formed from the digits above,
Repeating of digits are not allowed
Note: 
Permutation method would work if 0 was not included with the digits given