Starting with the two two-digit numbers

ab and cd, where ab > cd,

concatenate them to obtain the

four-digit number abcd.

(note: each of the numbers: a,b,c,d are digits)

If you subtract the difference between

ab and cd from abcd, you obtain 5689.

Determine the number cd.

Last puzzle that I posted. There is no one solve it. I will post solution up this weekend...any suggestions ? and here is a little bit easier puzzle