He doesn't need to repeat things often to learn them, but he has trouble holding things in his head and manipulating them. This is why mental math hasn't been his strong suit. He does better if he can write things down so that he doesn't ahve to hold things in his head.
Like Kriston's ds, mine (also with average Working Memory) seems to have trouble keeping things in his head... We use Singapore Math and I think the emphasis on mental math has been a good challenge for him, though he struggled at first. Years ago, working with multiple digit addition and place value, he'd only be able to keep one place value at a time in his head. It still frustrates him, and he strongly prefers pencil and paper for math.
His long term memory is great, though. Some information seems to go straight there! (The kid can recite more bits of information about WWII and dinosaurs than I've ever heard and has an incredible visual memory for artistic detail.)
