Question 63
A $4 \times 4$ magic square has in its first line the non-nil digits $a, b, c, d$, written in this order (from left to right), and each of the other lines contains the same numbers, written in different orders. It is known that the sum of the eight four-digit numbers obtained by reading the columns downwards and by reading the lines from left to right equals $59994$. Find the largest and the smallest possible value for $abcd$.