Question

Q.1)How many 3-digit numbers can be formed by using the digits 1 to 9 if no digit is repeated?
Q.2)How many 4-digit numbers are there with no digit repeated?

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Answer 1

out of

9999 - 999 = 9000 ,

1111,2222,3333,4444,5555,6666,7777,8888 = 8

9000 - 8 = 8992