Various thoughts about CIDR & speed & CCNA exam + changes (secondary) ...

I was reading the other day:

when I stumbled across these comments (see the first article, with Richard's notes from his start of CCNA training):

"Todd is an excellent instructor, and he's already improved my subnet addressing skills by an order of magnitude. In other words, subnet questions which might have taken 60 seconds to answer will probably take about 6 seconds. This speed increase is important, as candidates have about a minute to answer each question. They can't return to skipped questions, so it pays to answer as rapidly as possible."

which led me to relate this to an older issue, which I found pretty useful (personally), from Barry Margolin's EXCELENT comment and description of algorithm:

and - then - to asking all of you, here:

What mathods have you found useful, and willing to share, in regards to speeding up the subnetting "mental" calculations? In my opinion, for a person like Richard to recognize one order of magnitude gain in doing this should be taken quite seriously ... any comments?!?

By the way - worth reading Richard's further notes, about his CCNA endeavor, following the orginal blog (Notes from the CCNA class) - they point out some changes in the exam:

TIA, Papi