Tutorials questions

[mawi2k]

I'm enjoying going through the tutorials (see previous pointless query by me), but found another inaccuracy. Unless I've forgotten my binary, "16"="10000" (not "11111" as written in the tutorial, which is "31"). 
http://techsupt.winbatch.com/webcgi/webbatch.exe?techsupt/nftechsupt.web+Tutorials+Boolean~Math~and~Boolean~Algebra~Refresher.txt

Not sure if I should be writing in here for these, so if there is another better address let me know, and I'll send any such that I find in future as you request.