Super useful for differentiation!
I think this is a great resource, in particular for Physics and Math courses. The pre-made practice problems are a great way to give students extra practice without having to search or make my own, and the automatic grading saves me hours of reviewing individual assignments.
There are multiple different Physics courses on Khan Academy (I teach Physics). This is so helpful because if one course does not have what I'm looking for in particular, I can search in the other courses and will likely find what I need.
I wish some of the sections were more in-depth, or that they were consolidated in some way. Perhaps practice problems could be customizable, seeing as the problems given to students are randomly selected from a group of options. Some practice sets are half composed of problems that I want my students to practice, but I cannot assign them because my students haven't seen the other half yet.
Overall, this website is a fantastic tool to supplement learning done in the classroom and at home. I've had great experiences with this tool both as an educator and as a student myself, when I went through high school.
How I Use It
I've used this tool primarily to supplement learning outside of class. While we have spent classtime working on Khan Academy practice, I usually try to focus on examples and instruction in class, then recommend certain videos and assign practice problems for homework.