(5 x 4 x 3 x 2) = 120 of them, if no digit can be repeated.
If digits can be repeated in the same number, then 3,125numbers can be formed.
100,000
12
24
There are 504 such numbers.
823543
13579
As there are 5 different digits, allowing for repetition of a digit, the first digit can be any of the 5, and for each of these, the second can be any of the 5, and so for the third, making: 5 x 5 x 5 = 125 different 3-digit numbers.
9999
100,000
12
512
24
There are 504 such numbers.
There are 60480 numbers.
840
823543
6