I keep trying to explain to people that you keep subtracting something from itself as it goes along, and you get the difference table. Then if you add the differences back together, you get what you started with, except no starting position, which is the confounding fact. XD Poor mans calculus, useful when you have tabulated data but no equation - so its actually sometimes the only way to do it, even though its much easier to do than doing maths normally. youd almost call it completely childish. But noone understands out of my two partners here at my house, they just think im telling them lies, and going crazy, which is what happens when you talk to people that dont understand you, happens in every way every place, every time of your life. And I do it to other people too. Just doing calculus like a bum, gets you really far! Learning about functions! input and output, add and subtract, relative and absolute. Without doing a shred of true integration, derivation or algebra or factorization, just think about the simplicity of it, is a very useful thing, without reading a single maths book to the end or understanding a single professor there is!