Help needed in sfm urgent

Hi Friends I have been studying SFM from JB Gupta and not able to understand derivatives and portfolio properly. what would be weightage of these topics in paper ? Please help to make strategy for clearing SFM if I leave these 2 topics. Will it be possible to clear paper after leaving these topics. Or what should be the way to learn these chapters if don't require to leave. Please help me. Regards Deepak Arora