There are 504 such numbers.
If repetition is allowed . . . . . 343 If repetition is not allowed . . . . . 210
64 if repetition is allowed.24 if repetition is not allowed.
15 of them.
There are 5*5*5 = 125 such numbers.
Six (6)
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
There are 60480 numbers.
There are 3024 of them.
If repetition is allowed . . . . . 343 If repetition is not allowed . . . . . 210
64 if repetition is allowed.24 if repetition is not allowed.
15 of them.
There are 5*5*5 = 125 such numbers.
Six (6)
There are 600 such numbers.
There are 2000 such numbers.
I take it that you want to make three digits numbers with 8,7,3, and 6 without repetition. The first digit cane be selected from among 4 digits, the second from 3 digits, the third digit from 2, hence the number of three digit numbers that can be formed without repetition is 4 x 3 x 2 = 24
if the repetition is allowed the there is 6*6*6 possible ways = 216