This video explains very clearly and precisely one of the most important topics in Calculus: the area under a curve. It starts out with approximating using rectangle areas at a very theoretical and high level. Some of the terminology and notation is above a beginning Calculus studentâs level. Some concrete examples are also used, however, which are more accessible to the majority of students. You will also learn how to find these sums on a graphing calculator. In the end, the video leads up to finding the exact area under a curve by finding the integral.