Trigonometry - What's the Simplest Way to Define What Calculus Is?

calculus is a way of dividing things down into infinitesimal parts and then adding all those parts up. So instead of doing math with discreet numbers, like two plus two equals four, or like real simple, calculus can handle really messy things, like really, really messy things. If we were to use old school math, we would say, ok, well, it's going to be tilted back this much for two seconds... But there's probably more than one force acting on that.