Scottish student applying to UC universities

as an international undergraduate student I hope to apply to USC, Berkeley of business (and most other UC uni’s) and to UCLA for business and economics, I’m also going to sit the SAT reasoning test, I have math as a GCSE.
will I need (Scottish) higher maths to be accepted to these courses ? will I need any specific classes at higher and are these business courses hard to get into.

Not required, but an SAT subject test in math wouldn’t hurt if you think you would do well. UCs require 2 years of secondary school math for US students, and prefer three & your GCSE would count as the 2. Assume you know that you need 5 GCSEs and 3 A levels.