Websites to improve maths problem solving?Watch this thread
Just started a levels and I think that practice is the most important but sometimes you would get harder questions that you won’t understand and improving problem solving can help that. I know I can just do more difficult questions on that topic but they’re usually harder to find or there are very few of them.
For problem solving, you could look at
as well as the ukmt/aops links above. The ukmt smc is coming up shortly, why not do a few past papers as a time effective way of seeing how you get on? There are some basic problem solving techniques about trying extreme cases, sketching, working backwards, spotting patterns, ... A reasonable bit of advice is that the jmc is pretty much 90% related to gcse, imc 70% related to gcse but the smc is 20% related to A levels. Obviously these numbers are rough, but don;t think its absolutely necessary for A levels.
Similarly the mat, step
Has teaching material/questions which stretch you, though these are primarily for maths entrance exams and not necessary for A levels (regard them as extension material). The book starts off with good advice about problem solving.