If you'll accept a decimal, then it's .0123456789
If you want whole numbers only, and you'll accept a leading zero, then it's 0,123,456,789.
If not, then it's 1,023,456,789.
1,234,567
The smallest 4-digit number without any repeated digits is 1023, as it starts with the smallest possible digit (1) followed by the next smallest digits (0, 2, 3). The largest 4-digit number without any repeated digits is 9876, which uses the largest digits available in descending order.
The smallest four-digit number in which no digit is repeated is 1023. It starts with the smallest digit (1) to ensure it's a four-digit number, followed by the next smallest digits (0, 2, and 3) without any repetitions.
5
The smallest 10-digit number with no repeated digits is 1023456789. This number starts with 1, the smallest non-zero digit, followed by the remaining digits in ascending order, ensuring all digits from 0 to 9 are used exactly once without repetition.
5
none
0132 or 1234 0123 or without 0 at front = 1023
The smallest number with no digits repeated would either be zero or one, depending on the set of numbers you want to choose from.
102
10234567
1023456789