some people, who have Aspergers, will latch onto something they understand and become extremely good at it. it does tend to be something black and white, right or wrong, such as maths, science etc. i have had students with Aspergers and they are awesome in some classes and really bad in others, you have to find their passion and then let them run with it. this goes with the repetition thing that people labelled with autism do, because it helps them stay centered in a situation they are not happy, maths and counting is a good one but repetition is good for learning maths so this is why they become good at it. Some of the stuff I latch onto is Motorbikes & Computers