The four digits can be used to produce infinitely many different numbers if repetition is permitted.
Without repetition, there are 24 possible numbers.
A lot more can be produced if the numbers are combined using binary oprations, fore example, 19 * 8/4 = 19*2 = 38.
4!=4x3x2x1=24
10+23 = 33
There are 360 of them.
210
9
Assuming you mean four different numbers, 0.123
2222
4!=4x3x2x1=24
If the digits are all different then 18. Otherwise, 192.
10+23 = 33
the least number is 210 which is divisible by four different prime numbers.
There are 360 of them.
24, if you permit numbers starting with 0, 18 otherwise.
210
1023
40,50,80,64
$400,000,000.