A level mathematics + further?

Normally in as you would do c1 c2 and s1, then in a2 go on to do c3 c4 and either s2 d1 or m1. The core maths modules are mainly about differentiation and integration. Sin tan and cos then come into this in c3. S1 is mainly do to with problem solving and averages and probability trees. S2 then goes onto distribution, including normal, poisson and binomial. You need to work hard at the start in order to understand it and not fall behind, it will be hard to catch up if you do! Good luck