document.write( "Question 1011202: how many number of 9 digits can be formed which have all digits different?
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #626782 by mathmate(429) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "Question:
\n" ); document.write( "how many numbers of 9 digits can be formed which have all digits different?
\n" ); document.write( "
\n" ); document.write( "Solution:
\n" ); document.write( "Numbers do not normally have a leading zero, so a nine-digit number cannot have a zero as the first digit.
\n" ); document.write( "Examples: 123456789 is a valid 9 digit number with distinct digits, but 012345678 is not considered a valid 9 digit number (for the purpose of this question).
\n" ); document.write( "
\n" ); document.write( "A nine-digit number with distinct digits will have 9 choices for the first digit (1-9) and 9 choices for the second digit (0-9, less the first digit), then 8 choices for the third, etc.
\n" ); document.write( "So the total count (N) of numbers with distinct digits is then
\n" ); document.write( "N=9*9*8*7*6*5*4*3*2=9*(9!/1!)=3265920
\n" ); document.write( "
\n" ); document.write( "Note:
\n" ); document.write( "If the answer is 910, it may refer to a different question, or a question worded differently.
\n" ); document.write( "It might help if the question could be posted exactly as it appears.
\n" ); document.write( "For example, the answer to the question \"how many ways to choose up to 9 different digits out of the digits 0-9\" would be 1022. \n" ); document.write( "

\n" );