Hi Shellymos,
I know what you mean w/not wanting to teach him the wrong way.
I know for sure when my DS6 switches to public in Sept they teachers will not know what the hell he is doing when he does borrowing. I know that for sure! So I hear it is good to teach different methods. Although I don't want to confuse him so I havent taught him the way I learned it. I guess the school will teach it anyway and then I will see if it confuses him.
I think since they are smart they will have no problem learning different ways to do math problems.