IBM Ponder This #131 · March 2009

Because February's challenge was very difficult, we postponed the submission deadline by a month and we'll post the solution on April 1st. In the meantime, here is a more straightforward challenge:

There are several simultaneous solutions for the following two exercises (the second is a 90-degree rotation of the first):

  a b c      g d a
+         +
  d e f      h e b   
  =====      ===== 
  g h i      i f c

One of them is

5 8|3
   |
1 4|6
===+=
7 2|9

Our challenge is to find a similar exercise in hexadecimal.

One can prove that a 4x4 is insolvable, so we added a few zeros and ask you to fit all 15 nonzero hexadecimal digits in

  abcde       mjfa
+ fghi0       nkgb
  jk00l     + 00hc 
  =====       00id
  mn00o       ====
              ol0e

Solution

Best opened after a real attempt

To be added.