There are 27 of them.
234, 243, 324, 342, 423, and 432.
If you can repeat a digit, there are 27. If you can't repeat a digit, there are only 6.
012345 or -543210, if negative numbers are permitted.
972.
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.
You can select 9 numbers for the first digit, 8 numbers for the second digit, and 7numbers for the third digit; so 504 (e.g. 9*8*7) different three digit numbers can be written using the digits 1 through 9.
six
Using division or multiplication or addition??
it would be 0000.01
81 As there are no limits stated then you can have a number comprising a repeated single digit (such as 2222), two pairs of numbers (e.g. 2244) or three different numbers (such as 2462). The first digit can be one of any of the 3 numbers. The second digit can be one of any of the three numbers, as can the third digit and also the fourth. Then you can have 3 x 3 x 3 x 3 = 81 different 4-digit numbers using the three given numbers.
Using prime factorization, there are 2 three digit numbers with 9 factors: 512 and 768. There are no three digit numbers with 10 or more prime factors. 512=2^9 and 768=3*2^8
6 possible 3 digit combonations
24 three digit numbers if repetition of digits is not allowed. 4P3 = 24.If repetition of digits is allowed then we have:For 3 repetitions, 4 three digit numbers.For 2 repetitions, 36 three digit numbers.So we have a total of 64 three digit numbers if repetition of digits is allowed.
48 of them if digits may not be repeated. 100 if they can.
10
100122 or, if negative numbers are permitted, -998877