In order for the number to be less than 500 the first digit must be 3 or 4. The second digit can be any of 3,4,5 or 6 not equal to the first and the last can be any of 3,4,5 or 6 not equal to the first or the second. This leads to the following 12=2*3*2 possibilities:
345 435
346 436
354 453
356 456
364 463
365 465
It is 120 if the digits cannot be repeated.
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.
987,653
500
jfnvjsdkncjfdknvlakdjvbsadoihfcb shfvbcnsHLfc bnshJCbvjhbeshuyvbe b hdfbgehfgbwahucgbvfer fguy gyfuby uyr
1 set
It is 120 if the digits cannot be repeated.
It is possible to create a 3-digit number, without repeated digits so the probability is 1.
757
Using the digits of 1345678, there are 210 three digit numbers in which no digit is repeated.
987,653
9x9x8x7x6x5x4x3 =1632960
27 three digit numbers from the digits 3, 5, 7 including repetitions.
24
500
jfnvjsdkncjfdknvlakdjvbsadoihfcb shfvbcnsHLfc bnshJCbvjhbeshuyvbe b hdfbgehfgbwahucgbvfer fguy gyfuby uyr
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.