There are three activity pages. The first screen is shown below.

Students select one of several functions graphically, and then define the endpoints of an interval via mouse click. Working with that one interval, various options for defining a rectangle are available: left endpoint, right endpoint, midpoint, or a point selected by mouse click. The determination of the height of the rectangle is then shown dynamically, as is the area thereby defined.

The second screen has a similar layout, but provides an additional window for accumulating the terms of a Riemann sum. An image of this screen is shown below.

Here, students use mouse clicks to build up a Riemann sum one rectangle at a time. For each rectangle, the mouse is used to define the right endpoint of the base interval. Then the student selects an option for defining the height of the rectangle. The options available are the same as on the previous page. As each rectangle is defined, its area is computed (and displayed dynamically), and added to the running total that is accumulating the Riemann sum.

On the final screen, left and right endpoint sums are automatically generated for various functions. See the screen image below.

Here, the goal is to experiment with the convergence of left and right endpoint sums to a common limit. The partitioning of the interval and the determination of the heights of the rectangles are automated. Students simply set the number of rectangles using a slider bar, and then click buttons to obtain the left and right endpoint sums, along with graphical depictions of these sums. As before, students can choose from a variety of functions, and set the endpoints for the interval over which the Riemann sums are computed.