True. A teacher may be able to help find you a tutor or he/she might tutor you them self.<span />
I believe the answer is: Mathematics
This happen because being good mathematics is strongly correlated with IQ score analytic type intelligence. Not only that, almost all subjects (beside language) would implement the lessons that taught in mathematics as a part of their curriculum.
They need it because if not then if someone was to come to America from the UK they wouldn’t have any way to get to money. So there is exchanging so you can get the money here worth the money there. Hope this helps. It’s kinda hard to explain lol.