A block of calendar dates has the numbers through in the first row, though in the second, though in the third, and through in the fourth. The order of the numbers in the second and the fourth rows are reversed. The numbers on each diagonal are added. What will be the positive difference between the diagonal sums?
This problem is copyrighted by the American Mathematics Competitions.
Instructions for entering answers:
For questions or comments, please email email@example.com.