So this is f of 2.5. Remember, in each of these, I am just looking at the left boundary of the rectangle and evaluating the function there to get the height of the rectangle. Now that I set it up in this way, what is the total approximate area using the sum of these rectangles? And clearly, this isn't going to be a perfect approximation. I'm giving up on a bunch of area here. Let me see if I can color that in with a color that I have not used. So I'm giving up this area.