I would imagine you would have to change schools entirely. Could he do maths on line?
I think that this is the best option - because, I am not sure that you can tell the administrator your real reason for asking for math at the other school - what can you possibly say - that this teacher is bad/not doing her job/not treating your DS fairly? If you did, then it makes the admin of the school look bad - as if they are not in control of the situation - to such an extent that people are moving to other schools for a single subject due to the poorly run math program?
Since the other school is very close to you and the math program is what you would like, why not transfer to that school and move on? I am sure that it is a winning solution for your DS.
