Originally Posted by
Tankengine
Imagine you are at the runway, about to take off.
You have just swapped ends, are you going to open up the AIP and look at figures?
Some stuff you just need to know!
Not sure what you mean buy "swapped ends" but the idea that one would need to remember, let alone make calculations from these numbers while in the cockpit is ... well, quaint, at best. Any necessary calculations involving those numbers have been accomplished long before you walk out to the airplane. Generally, by someone else. Even if you did memorize those numbers, you would not have the obstruction data needed to apply them in calculations, so being able to recall the numbers is pretty much pointless in the real world, outside exams.