Same for my son who is really talent in maths, and what we do when he was 2 is playing counting in food, e.g. he wants 5 crackers, then i point to his plate and said, "u already have 3 crackers on your plate, how many should i give u to make it 5?" u will be surprise that he answer "2" without thinking :P, that's already addition and subtraction. We always did it when we went to parent co-op preschool (as i don give him crackers, only the sch will give him), when my son was 2.5, he suddenly do additions by counting fingers, after a while, he did mental additions (e.g. 8+7=15).
