111, 112, 113, 114, 121, 122, 123, 124, 131, 132, 133, 134, 141, 142, 143, 144,
211, 212, 213, 214, 221, 222, 223, 224, 231, 232, 233, 234, 241, 242, 243, 244,
311, 312, 313, 314, 321, 322, 323, 324, 331, 332, 333, 334, 341, 342, 343, 344,
411, 412, 413, 414, 421, 422, 423, 424, 431, 432, 433, 434, 441, 442, 443, 444,
There are 210 4 digit combinations and 5040 different 4 digit codes.
Any 4 from 10 in any order = 10 x 9 x 8 x 7 = 5040
There are 4 possible numbers if the digits are not repeated; 18 if they are. Those are 3-digit numbers, assuming that zero would not be a leading digit. If zero is allowed for a leading digit, then you can have 6 for the non repeated, and 27 if repetition.
10,000
There are 256. Some of them are: 1111, 1112, 1113, 1114, 1121, ... 2111, 2112, 2113, ... 3111, 3112, ... 4111, etc.
There are 210 4 digit combinations and 5040 different 4 digit codes.
There are 10000 such codes. Each of the numbers 0-9 can be in the first position. With each such first digit, each of the numbers 0-9 can be in the second position. With each such pair of the first two digits, each of the numbers 0-9 can be in the third position. etc.
Any 4 from 10 in any order = 10 x 9 x 8 x 7 = 5040
1,000 of them. The list of possibilities will look exactly like the counting numbers from 000 to 999 .
1000
There are 4 possible numbers if the digits are not repeated; 18 if they are. Those are 3-digit numbers, assuming that zero would not be a leading digit. If zero is allowed for a leading digit, then you can have 6 for the non repeated, and 27 if repetition.
The possible 4 digit codes using the numbers 0-9 are every number between 0 and 9999. For numbers that have less than 4 digits, just precede the number with 0's. 10,000 possibilities
Total number of possible 3-digit numbers = 9!x10!10!
10,000
103 = 1000 in all.
9999999999 100000000
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.