And then what I'm left with, and I will switch to a neutral color, if I factor out a delta x over 2, then I have just an f of 1, and then I have 2 f of 2's, so plus 2 times f of 2, and I'm doing this because you might see a formula that looks something like this in your calculus book, and it's not some mysterious thing, they just really summed up the areas of the trapezoids. And then we're going to have 2 f of 3's, plus 2 times f of 3's, plus we're going to have 2 f of 4's, plus 2 times f of 4, and then we're going to have 2 f of 5's, plus 2 times f of 5, and then finally we're going to have 1 f of 6, plus f of 6. If you were to generalize it, you have one of the first endpoint, the function evaluated at the first endpoint, one of it at the very last endpoint, and then two of all of the rest of them. But this is just the area of trapezoids. I'm not actually a big fan when textbooks write this, because when you see this, it's hard to visualize the trapezoids. When you see this, it's much clearer how you might visualize that. But with that out of the way, let's actually evaluate this.