This is a nice little app to be used in Calculus to reinforce and practice derivatives. There are 9 lessons ranging from differentiating using the basic rule to differentiating with fractional exponent to the product rule. Each section has a video, a final answer which shows how they got the answer and more practice problems. This app is great for reinforcing the material taught in class and it provides a nice amount of practice. I think this app would provide excellent practice for my calc students.