Growing up in Indonesia, our family had a "belimbing" tree that also has fruits on its trunk. Belimbing fruits are *extremely* sour and we'd dare each other to eat 'em.
That's pretty scary - kids don't have a good grip on their emotions, and there's only so much parents can do to make sure there are no ways they can "accidentally" strangle themselves.
I used to read a lot of Ludlum's book, but stopped when I was reading something and thought it was so familiar ... turned out I had read it before! That's when I realized that his books were very formulaic.
8432 - 2348 = 6084
8640 - 0468 = 8172
8721 - 1278 = 7443
7443 - 3447 = 3996
9963 - 3699 = 6264
6642 - 2466 = 4176
7641 - 1467 = 6174
Your first step was incorrect
Started reading Frederick Forsyth afterwards :)