I missed Calc in hs/undergrad but need it much more later on (and felt pretty innumerate without it), I remember picking up the classic "Calculus Made Easy". I

I missed Calc in hs/undergrad but need it much more later on (and felt pretty innumerate without it), I remember picking up the classic "Calculus Made Easy". I was immediately stunned by it's simple description of integral: "Now any fool can see that if x is considered as made up of a lot of little bits, each of which is called dx, if you add them all up together you get the sum of all the dx's (which is the same as the whole of x). The word 'integral' simply means 'the whole'" After reading this and more I asked a few people who I know knew calculus how they would explain an integral (figuring that they would give a similar definition and would delight in finding a book which explained it so clearly) and was shocked to discover how many could calculate it without really understanding what it was or at least being able to describe what it was in clear terms