Take a look inside 8 images
Art of Problem Solving
Pros: Presents information in multiple ways; courses are organized specifically by grade level.
Cons: The forums are a bit hard to navigate; continued use of the program could get a bit pricy over time.
Bottom Line: Separate sections for younger and older students help to teach kids at all levels, from foundational skills up to Math Olympiad training.
The Art of Problem Solving allows students to focus on math concepts that they're struggling with or (for advanced students) that offer a challenge. The site presents the materials as self-paced for younger students or as online, interactive courses for older students. There's also a large collection of additional resources available on the site, including videos and an extensive forum (over eight million posts and counting) where students discuss all sorts of math concepts.
The site is best designed for students wishing to work independently on their math knowledge, although some of the materials presented -- such as the videos -- may be good for a teacher to use with a whole class to introduce a topic or give a different perspective on it. If you're a Math Olympiad coach or have students preparing for math contests, you'll find the videos of sample test questions very helpful; many of the resources found here are especially geared toward kids who are preparing to compete at a national level.
The Art of Problem Solving has added a lot of math content over the past few years and now includes videos, interactive courses, and a fun, game-based academy for younger students. The site is divided into different sections, each focusing on a different area of math and different grade levels. The main divisions are AoPS Online, Beast Academy, and AoPS Academy.
AoPS Online provides older students with lessons on everything from pre-algebra foundational skills up to Math Olympiad training. There's also a substantial forum where students can interact with one another to ask -- and answer -- various math problems. The Beast Academy is for younger students and has a fun interface with comic characters, videos, games, and more for grades 2 to 5. Finally, the AoPS Academy is an in-person academy that students can attend.
Overall, the Art of Problem Solving provides a variety of resources to help struggling students succeed and to encourage and build enrichment for students to challenge themselves. The fact that it's all presented together in one place may also have the bonus effect of encouraging once struggling students to take on greater and greater challenges -- and perhaps be the next Math Olympians.
The choice of videos, books, forums, online interactive classes, and games (for the younger students) means that students have a number of different ways to learn the material. The Beast Academy, in particular, is very good at providing students with different learning options. The bright colors and fun characters also lend an air of friendless to the site without losing the focus on teaching.
The forum promotes collaboration among students, but it's hard to navigate, and some of the posts are less about math and more about "kids being kids" in an online environment. But for those who take the time to explore, there's a rich source of information to be found.