Question

how many 9 digit number of different digits can be formed​

Answer 1

Answer:

Step-by-step explanation:

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Answer 2

Answer:

Hope it helps

Step-by-step explanation:

First digit from the left can be filled in 9 ways (excluding '0'). Now nine digits are left including 'O'. So remaining eight places can be filled with these nine digits in 9PS ways. So, total number of numbers = 9 x 9P8 = 9×9!