I believe one of the most underrated math/coding websites of all time is projecteuler.net. As one of the top 2000 ranked in this website, I feel like I can say just how amazing this website is. Here is a list of everything I love about it.
Well thought out idea: This website is full of math problems in which (almost) all of them can only be solved by code, but you cannot just use brute force. You need to use the best of math and CS to solve the problems.
Good problems, and not just a couple. This website has >900 well thought out problems that can be solved in under a minute even on incredibly slow computers
Variance in difficulty: There are problems that will take you under 5 minutes to complete, and others will take you weeks without making a lick of progress (looking at you #177). Even if you don't know anything about number theory or CS, there will be problems you can solve and learn new concepts with. Just don’t skip to the recent problems, they're VERY hard.
Price: I won't sugarcoat it. It's free. Completely. No need to pay for problems. No missing features. No ads. Anyone can make a free account and have the exact same experience. This might be it's biggest selling point in my opinion.
These problems have made me spend hundreds of hours confused and dumbfounded until I find a solutions. Now, there are definitely sites you can find that will give you the answers But don't use them for solutions or else you'll be cursed for life. They're good places if you want to see how others solved it, but it is 233168% better to just skip on these websites and solve them yourselves. Even after all of this time, I have never copy-pasted an answer, purely because I prefer the struggle, and I believe that I learn more by finding out the necessary info myself.
Overall, stop reading this and go to the website (projecteuler.net). It deserves all the praise it can get. I hope you enjoy the problems like I do :)
