Okay, listen MU you need to understand that in AS and A2 you have to pick 4 options overall from 7 ones.
The 7 papers are :
Paper 1 : P1 Pure Mathematics 1
Paper 2 : P2 Pure Mathematics 2
Paper3 : P3 Pure Mathematics
Paper 4 : M1 Mechanics 1
Paper 5 : M2 Mechanics 2
Paper 6 : S1 Probability and Statistics 1
Paper 7 : S2 Probability and Statistics 2
Okay now you can choose for AS one of the following combinations :
Pure 1 is compulsory.
1) Pure 1 and Mechanics 1
2) Pure 1 and Pure 2
3) Pure 1 and Statistics 1
For A-level :
Pure 1 and Pure 3 (compulsory) with either :
1) Mechanics 1 and Statistics 1
2) Mechanics 1 and Mechanics 2
3) Statistics 1 and Statistics 2 Now I did for A-levels P1, P3, M1 and M2.
But I'd suggest you take P1, P3, M1 AND S1, since P1, M1 and S1 are AS subjects so they will be easy.
I hope you got anything from the above explanation.
You should also check the syllabus for each of the 7 options and see which suits your mind better. >>
http://www.scribd.com/doc/9907089/A-Level-Mathematics-2009