I have trouble understanding chapter 6 especially the grammar part and implementing the token functions expressions(), Token::get etc. I don't know how expressions work through the grammar; simple expressions like 2+3 I get it but something complex like (2*3)-(4*2) confuses me. I've read this chapter countless of times but still couldn't get it. That being said I also don't know how to solve question 3 and don't know where to start. Anyone can help guide me through this? .