Week 7 - Recursion

Actually, the first time I learnt about this topic is in week3, but until now, I can say that I haven't totally understand the way to use it. It's really a hard part for me, sometimes i just know that i need to use recursive codes to solve the certain problem, but just don't know how to write. For example, i failed to finish writing codes solving 'counting 2' problem in the term test which really makes me a little bit sad :(. I think the only way to get more familiar with recursion codes is to trying more recursive problems and to actually understand the codes.