I first discovered Khan Academy three years ago. My daughter was doing Algebra and there were some things that I just couldn't explain in a way that made sense to her. So, I searched the internet for Algebra videos and stumbled upon some videos by Khan Academy that helped her progress through her Algebra textbook without any help from me.
Over the years, the website had grown and we have come to rely on it for much more than Algebra explanations.
First, I find that Khan Academy, is an excellent resource to use when you don't understand a concept. The video library covers every topic found in basic math, Pre Algebra, Algebra, Geometry, Calculus, Civics, Art History, Banking, Biology, Chemistry, and many science topics. If the kids don't understand a lesson from any text book, I know where to look.
We have also found Khan Academy to be very useful for test prep. There is a set of videos that correspond directly to a SAT prep book. This is very useful in figuring out where you went wrong in test practice. In addition, there is an exercise dashboard that students can use as either a full curriculum, or to fill any mathematical holes in their education. My kids use it for test prep reminding themselves of any types of problems they may have forgotten in the past.
As I also help other homeschool families get started and/or get over tough spots in homeschooling, I also function as a coach. Khan Academy has made it possible to monitor progress of students online, so that I don't need to be standing over them to make sure their work is getting done.
From the time I found Khan Academy to now, the site has become more and more valuable to me as a homeschooler. I anticipate that this online curriculum will make it possible for more and more families to be able to homeschool.