I'm thinking of taking an extra module to increase chances of an A* in A2 Further Maths Edexcel, and I was thinking of taking S3 but on TSR I've heard many say that S4 is a lot easier and that S3 is the hardest stats module.
1. Is it possible to take a more advanced module having not taken previous ones? E.g. FP3 without having done FP2, D2 without having done D1
2. If so, is learning S4 before S3 even a viable option? Or would not knowing S3's content prevent me from learning S4 effectively