Calculus Bonus
posted by Matt on .
Form two fourdigit numbers from the digits 2, 3, 4, 5, 6, 7, 8,
and 9, using each digit exactly once, so that the absolute value of
the difference of the two numbers is as small as possible.
I don't know where to start, any help would be greatly apprecitated.

How about 2345 and 1986 ?