I'll toss out some new ideas in hopes of finding that first piece of instructions that I think you have.
Start with top of page 20. Do what you did to answer chapter question 1. (Ironically, I think you might be the only one who would get this anyways, mostly because of the pen and paper methods) Make sure you write things down exactly and double triple check. Its easy to make a mistake.
Do this for the whole page. Then go backwards from where you started and see what you find.
There is more than one half to the story. Remember chapter 13 1/2? There is also an explanation for what is missing and its not a mistake.