Which number is the odd one out?
the one that stands out is 255(1) being an odd number at the end, but I think this is to easy
2551, 3774, 2958, 4590, 1224 and 1836
I think I have the answer. For each four digit number make two columns.
The first column is the 3rd minus the 1st digit. The 2nd column is the 2nd minus the 4th digit. When rearranged this gives:-