Amazing resource It's the kind of resource that any student should have. It has a great approach, and you learn by doing. Besides the website being an amazing tool, their team is incredibly responsive and helpful for any support issues.

A great app for learning A great app for learning. Sadly though, I didn't have time to use it and had to cancel my subscription only to realize that the said subscription already started. However, with their great support, they were able to help me sort it out with a refund. Nothing but great experience so far. I highly recommend it!!

Disappearing classes Although the classes are interesting and the math is (sometimes) well explained, there are also a lot of issues with Brilliant: *Classes disappearing in the middle of doing it. Algebra 2 for example *Classes skimming through essential piece of information, e.g. Introduction to linear Algebra. I'd really recommend a mix of other solutions if you want to further your understanding of mathematics. Khan Academy & 3Brown1Blue (and many other free resources) provide better explanation and have the same level of interactivity.

Great interactive learning tool Great interactive learning tool, works like duolingo but for maths!

Good for children (i guess) The idea is cute but imho accomplishes nothing. It tries to "gamefy" the learning experience but just muddles the learning in the process. I can see this being a fun way to learn about our world for small children or maybe young teens, but the site is definitely marketed towards all age groups. Just reading the wikipedia article about whatever subject you want to learn will most likely get you a better grasp on the topic than spending money on the premium subscription, which a lot of it is being spend on making 'cute animations' and keeping the app running. I have yet to come across actual exercises which require any deeper skill whatsoever. If you have a small child at home which wants to learn about science and the like in a playful way or if you are an adult and want to feel like you are learning something new on your commute this is probably not something bad. For me though this feels like another attempt to make an app for something which does not need it. Buy a book instead.