DD is like this, too. She begs for new and exciting math concepts and terms, and totally gets them, but doesn't show her teacher she really knows subtracting within 20! She recently got interested in poetry again, which was her obsession last summer/fall, and because she hasn't thought about it since then she was excited all over. She was figuring out how many lines in different forms and rhyme scheme patterns, which she also did last fall. I mostly figure, eh, she's passionate about learning so that'll see her through. I wonder if its just asynchronous behavior, like she relishes these big concepts and patterns but the grind of committing them to automaticity is just not part of her mindset right now.