Find the difference between the greatest and the least number that can be written using the digits each only once.
Compute the required difference:
Here in the given digits is the greatest one digit.
Arrange the digits from greatest to least, that is, .
Similarly, here in the given digits is the least one.
Arrange the digits from least to greatest, that is, .
That is the difference between the greatest and least number is
= -
=
Hence, the required difference is .