After reading how to get cube roots in your head in a particular set of circumstances I learned the trick while stuck in traffic. But it then says you have to practice a lot so I wrote a tool in C to do that. But then I realised a web version might be a bit more accessible to people so here’s one.
Made the trainer work nicer on mobiles thanks to [Kae]’s suggestion.
Also made it a bit smarter in how it picked numbers to train on.
Math.random() didn’t seem that random on my machine so I made
sure it would provide all numbers from 10 to 99 if you did it long
enough. It favours non-divisible by 10 numbers more and it will
favour numbers you guess wrong more.