Important topics

All of the topics are important - partly because all are likely to be examined but also because so many of the topics build upon other topics. As far as what you call the 'theoretical part' that is about 50% of the exam (the other 50% involves calculations), but it not so much memorising but making sure you understand. They are in the exam to check that you understand the topics rather than have just learned 'rules'.

Thank you sir

You are welcome :-)