Just add one number by the easiest method (and yes, it is really easy if you understand the pattern). The published computer solution is computationally intensive. Just why did the computer choose cells (7,6) and (2,3)?
A really big clue the benefit of innumerate lawyers and doctors - the obvious cell to work on is (3,2)
The mathematical concepts behind many of my previous posts are much more difficult than this one.
Try this one first.
Published solution method