document.write( "Question 1195492: How many 5-digit numbers can be formed using numbers 0, 1, 2, …9, such that the first digit must not be 9 and repetition is not allowed \n" ); document.write( "

Algebra.Com's Answer #827996 by ikleyn(52832) $\"\"$ $\"About$

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\n" ); document.write( "How many 5-digit $\"highlight%28positive_integer%29\"$ numbers can be formed using $\"highlight%28cross%28numbers%29%29\"$ digits 0, 1, 2, …9,
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document.write( "Any of 8 digits  {1,2,3, . . . ,8}  can be in the first, most-left position \r\n" );
document.write( "    (everything except of 0 or 9),                                giving 8 possible options.\r\n" );
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document.write( "Any of remaining  10-1 = 9  digits  can be in the next position,  giving 9 possible options.\r\n" );
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document.write( "Any of remaining   9-1 = 8  digits  can be in the next position,  giving 8 possible options.\r\n" );
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document.write( "Any of remaining   8-1 = 7  digits  can be in the next position,  giving 7 possible options.\r\n" );
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document.write( "Any of remaining   7-1 = 6  digits  can be in the next (= the last) position,  giving 6 possible options.\r\n" );
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document.write( "The total number of 5-digit numbers satisfying the imposed conditions is  8*9*8*7*6 = 24192.    ANSWER\r\n" );
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\n" ); document.write( "\n" ); document.write( "To Alan:\r
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document.write( "    Alan, in such problems, the leading digit 0 is PROHIBITED by default.\r\n" );
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