everything is easy in context. what you are supposed to be teaching is not "what is easy", but how to put something in context to make it so. this typically means eliminating degrees of freedom--most of what you learn in school makes you smarted by limiting your cognitive overhead. the actual calculations are 1/10th of the cognitive load; that is why experience and not aptitude are valued later on. "hard" for someone with no experience is almost always not "intellectually difficult", its simply befuddlement.