Question

how many four digit numbers can be formed by using the digits 1 to 9 if repetition of digits not allowed?

Answer 1

hey dear
here is your answer ☆

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☞ there are four places in total.

First place can be filled by 9 numbers
Second place can be filled by 8 numbers
third place can be filled by 7 numbers
and finally
forth place can be filled by 6 numbers
reason - repetition of numbers is not allowed.

now total number of ways - (9) (8) (7) (6)
=>3024

hope it helps ✌ ✌