document.write( "Question 770081: Find the number of different number of 4 digits that can be formed with the digits 1,2,3,4,5,6,7. the digits in any number being all different and the digit in the unit place being always? \n" ); document.write( "
Algebra.Com's Answer #469309 by ramkikk66(644)\"\" \"About 
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document.write( "Digit in the unit place being what? Ok let's assume it is 2. Same logic will work\r\n" );
document.write( "for any different digit as well.\r\n" );
document.write( "If the digit at units place is fixed at 2, then to form the rest of the number,\r\n" );
document.write( "we have to choose 3 digits from a set of 6 (since 2 is already taken).\r\n" );
document.write( "First digit can be chosen in 6 ways, the 2nd in 5 and the 3rd in 4 ways.\r\n" );
document.write( "So total number of combinations is 6*5*4 = 120.\r\n" );
document.write( "Thus, the total number of 4 digit numbers, with each digit being different, and\r\n" );
document.write( "the unit's digit being fixed, is equal to 120.\r\n" );
document.write( "Hope you got it:)\r\n" );
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