I've seen the book, but I've personally found it not very useful for a person who wants to first get the basics. The natural number's game is actually quite fu

I've seen the book, but I've personally found it not very useful for a person who wants to first get the basics. The natural number's game is actually quite fun, and I did understand much better the language. And it's also interactive, so you can try your solutions, and there are hints when stuck.