GATE’27 PREP Discrete Mathematics & Rosen Book

Hi, whats your take on preparation of discrete mathematics from Rosen textbook while solving exercise questions and PYQs?

Will it be good be good strategy?

Or do i need to add extra resources for complete prep of discrete mathematics

NOTE: I am asking this because i find GC maths lectures very lengthy and i kind of like to read from references. I used to skip discrete maths questions and that has costed me 5-8marks this year. Looking for your advice