60
You have 5 choices for the 1st digit, 4 choices for the 2nd and 3 choices for the 3rd.
Thus, 5 x 4 x 3 = 60
99999
If you don't repeat, 20. If you do, 58.
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
4: 1999,9199,9919,9991
15 of them.
8.
There are 900 of them.
48 of them if digits may not be repeated. 100 if they can.
99999
If you don't repeat, 20. If you do, 58.
Assuming no repeated digits, lowest first, 20; in any order 120; Allowing repeated digits: 216
If the digits are all different then 18. Otherwise, 192.
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
There are 60480 numbers.
4: 1999,9199,9919,9991
15 of them.
Assuming each of the given digits can be used only once, the answer is 24. If not, the answer is infinity.